【OpenSea】 No need to pay for gas? How to List and Buy NFT at Polygon

The word “NFT” is gradually gaining recognition and the OpenSea market is expanding. However, it is a hurdle to enter the market if you have to pay a fee every time you list an item, isn’t it? Especially with ETH transactions, the high cost of gas (remittance fee) is a big burden for exhibitors (especially those who continue to work as artists).

However, what if you could exhibit or purchase artwork without incurring gas fees? The risk of gas fees and the stress of transactions would be reduced. That is the main feature of the Polygon network.

In this article, We would like to share with you the advantages and disadvantages of using the Polygon network.

What is Polygon? Is it true that you don’t need to pay for gas?

We would like to explain the Polygon network. The network has just been launched and the penetration is still in its infancy, but the number of users is increasing rapidly because of the greatest advantage of not having to pay for gas. Let us tell you why the Polygon network was created and how you should use it.

About Polygon

Polygon was launched in October 2017 as MaticNetwork with the goal of functioning as a second layer to ETH; the name Polygon’s token, Matic, comes from the early stages of Polygon’s development.

Polygon is building a decentralized ETH scaling platform and dApp (short for Decentralized Applications, a de-centralized system) to solve Ethereum’s problems, allowing money transfers with low transaction fees.

In recent years, the Polygon network has been used to compensate for ETH’s high fees (gas fees, described as Gas Fees) and very slow transaction times, which have been caused by the increased trading of NFTs using the ETH network.

Although the Polygon network has a shorter history than ETH, and trust in the network is not widespread, in February 2022, Polygon successfully raised $450 million in funding from Soft Bank Vision Fond2, Galaxy Digital, TigarGlobal (an American investment company), and others. In February 2022, Polygon Network successfully raised $450 million from Soft Bank Vision Fond2, Galaxy Digital, TigarGlobal (an American investment firm) and others.

Polygon Raises $450,000,000 From Sequoia Capital India, SoftBank, Galaxy, Tiger, Republic Capital

Currently supporting only the ETH basechain, the Polygon network also has plans to extend additional basechains based on community suggestions and consensus.

The supply of Matic tokens used by the Polygon network is 4,877,830,774 MATIC tokens in circulation, with a maximum supply of 1,000,000,000 MATIC tokens.

As of April 18, 2022, it is trading at ¥169.63/Matic.

Chart diagram of Polygon (as of April 19, 2022)

Do we need to pay for gas when listing or buying at Polygon?

One of the reasons for the Polygon network’s popularity is the low gas prices paid for transactions: there are no gas fees when listing or buying on the Polygon network.

Since the volume of NFT transactions has increased, the ETH chain has become overloaded and transactions (approvals) are taking longer. In some places, the ETH gas fee is not fixed as a percentage of the transaction, and more and more users are trading on the Polygon network as a second layer.

In June 2021, only 0.7% of transactions were made on OpenSea using the Polygon network, but by September this had risen to about 49%. The Polygon network is particularly popular for purchasing small amounts of NFTs, with about 77% of transactions using the Polygon network being under $100 (about $12,000).

I would like to list my work on OpenSea first. If you want to buy NFT pieces for a small amount, we recommend the Polygon network.

However, when you bridge (transfer) from the ETH network to the Polygon network, you will be charged for gas in ETH. If you bridge multiple times for each transaction, it will cost you more gas, so it is better to transfer ETH with a little extra time when you first transfer.

How to exhibit at Polygon

Once you understand Polygon’s network and the cost of gas, you can start exhibiting your artwork and photos. You will probably have a hard time at first, but let’s give it a try first. There are still very few people involved in NFT in Japan, so the sooner you get involved, the more business opportunities you will have.

Creating Collections with Polygon

First, you need to download MetaMask to your PC; it is safer to use the Google Chrome extension, because all OpenSea notations are in English, and you can use Google Translate in parallel. Naturally, you will also need the data (digital art, photos, videos, etc.) to be exhibited.

Open OpenSea and click on the icon in the upper right corner to Sign In and connect to MetaMask. Once connected, click on the icon again and open “My Collections” (4th from the top).

When the screen changes, click on “Create a Collection” and you will be prompted for the required information. Additional entries can be made later.

The logo image will be used for navigation. The featured page will be used for your own work on the homepage, in your category, and in the promotion area on OpenSea.

The banner image will appear at the top of the collection page.

The collection name can be any name you set up yourself.

The URL is the URL that will be used on your OpenSea.

You can set the description minutes and categories yourself, but you have a better chance of selling if you unify your items by collection: the pieces that sell well on OpenSea and the series listed at the top of the list are always united by the same character. Although the design of the character’s clothes and surroundings are changed, the series tends to sell better.

SNS links are also an essential part of your marketing strategy, so be sure to include links to Instagram and your own website, as these are the mediums through which you can introduce your work. Please make effective use of social networking sites to sell your work.

Creater Earning is the royalty you receive from the sale of your work after it is sold by the buyer. You can set a maximum of 10%. The seller will receive a percentage of each sale, even if the work was estimated at a low price and unexpectedly sold for a high price and sold in the secondary or tertiary distribution. The percentage should be set by yourself, but it is better to set a high value for when your own work sells.

The details of the blockchain settings are given separately, but you should specify either the ETH network or the Polygon network.

Although the initial setup is difficult, it is an important process for selling NFT works, so please make sure to fill in all the fields.

Adding an NFT item to your collection

Return to the top screen of OpenSea and click on Create to the left of the icon to get to the following screen.

Under “Create New Item” at the top of the page, there is a place to place art, photos, videos, etc. that you wish to exhibit. Drag and drop or select from a PC file the artwork you wish to display there. Enter a name, external link, and description.

For collections, select the section of the collection you have specified. (If there are multiple collections, specify the series.)

Supply is the amount of supply. Set the quantity of NFTs you wish to sell your work. Currently, only 1 can be specified.

Specify the ETH network or Polygon network for the Blockchain network, and press “Create” to add the items you wish to sell to the collection.

Selling NFT items you have created

To list your NFT item for sale, click “Sell” in the upper right corner of the NFT page you have created. The page will change, and you will need to set the selling amount (in ETH) and the selling period.


The selling price can be whatever amount you want to sell for, but you should take into account the price of gas when you sell on the ETH network. Also, 2.5% of the selling price is paid to OpenSea as a commission when a piece is sold. It will be deducted from the ETH purchased by the customer, but you should take this into consideration when selling.

Duraction refers to the selling period, which can be the initial six months. If you think you can sell more if you shorten the period according to your own sales strategy, you can set it shorter.

When you click “Unlock” on the MetaMask, you will be asked to sign the transaction. If there is no problem, click “Sign” to complete the listing of the NFT work.

Points to keep in mind when listing an item on Polygon

Although it is now possible to list an item on Polygon, there are some disadvantages. The fact that the initial setup is cleared and there are no gas fees when exhibiting is the biggest attraction, but there are also some points that require more work due to the ease of exhibiting. We would like to tell you about them.

Hard for collectors to recognize a piece if it’s not exhibited in Ethereum

If you look at OpenSea pieces listed on the ETH network, you will see a large number of entries and high prices; the NFT itself was created as a derivative of the ETH netchain, so it has the advantage of high recognition and a large number of users.

The Polygon network itself has a growing number of active users, but its market size is smaller than that of ETH. If you want to exhibit NFTs as a trial, we recommend the Polygon network, which does not require gas, but if you want your own work to be recognized in a larger market, we recommend that you exhibit on the ETH network.

NFT trading on the ETH Network is also equipped with an auction system. Although it is a global transaction, your NFT work may catch the eye of a wealthy person outside of the country and lead to an unexpectedly high transaction price. This will increase your visibility as an artist, and your chances of being recognized by collectors around the world will increase.

It takes a lot of work to switch back to ethereum from Polygon

If you want to try out selling your NFT work, we recommend the Polygon network, which does not require gas, but there are some disadvantages.

You cannot send the reward earned from the sale of your NFT work on the Polygon network directly to the Japanese exchange. If you send it by mistake, it will lead to self-GOX (loss of funds). Of course, you cannot directly convert the ETH you have earned into the any currance what you wish.

Assets earned on the Polygon network are called WETH (Wrapped ETH) and are priced the same as ETH, but they cannot be exchanged for cash.

Therefore, the WETH acquired through the Polygon network is re-bridged and transferred to the ETH chain net, where it is converted to ETH. Then, please remember that you will have to transfer it to a crypto asset exchange and convert it into any currency.

How to Purchase Polygon Works

Adding the Polygon (polygon) network to MetaMask

Here is the link to the official Polygon network website.

In order to purchase Polygon pieces, you need to add the Polygon network to a wallet called MetaMask, and since the MetaMask wallet only supports the ETH network if you just downloaded it, you will need to add the Polygon network yourself. You will need to add your own Polygon network.

To add the Polygon network to the MetaMask network

①Register MetaMask and log in.

②Select a custom RPC for the MetaMask network.

③Copy and paste the following URL and chain ID to register.

  • Network name: Matic Mainnet
  • New RPC URL: https://rpc-mainnet.maticvigil.com/
  • Chain ID: 137
  • Currency symbol: MATIC
  • Block Explorer URL: https://explorer.matic.network/

The Polygon network can now be imported.

Search Polygon Movies

Go to the OpenSea site and log in. To the right of the search area, there is an “Explore” section. Click there and open “ALL NFTs”.

Then the “Filter” function will appear on the left side. Click on the “Chains” item, and you will see a list of Polygon works.

Otherwise, you can search from there for collections already exhibited by artists you know, or NFTs in the categories you want.

Transferring Ethereum to Polygon

To purchase your first NFT piece, you must first buy ETH.

We will not mention exchanges, but domestic exchanges include Coin Check, Bit Flyer, GMO Coin, and Rakuten. Overseas, you can trade on Binance or Bybit, the world’s largest exchanges.

As of April 19, 2022, the price is 390,000 yen/ETH, but there are exchanges where you can buy ETH at a minimum price of 500 yen, so you can buy ETH with Japanese yen, which is a little more than the price of the piece you want.

Transfer the ETH you purchased on the exchange to MetaMask, which you downloaded to your PC or smartphone. You can have MetaMask log you in and copy the address under your account to send the money.

Once you have confirmed that you have transferred the money to MetaMask, you will need to transfer the funds from the ETH network to the Polygon network. Be sure to bridge from the following site. This may lead to loss of funds.


Click on Polygon Bridge, second from the left.

Deposit for remittance. Enter the amount you wish to transfer (in ETH).

At this time, please take into account the cost of gas you will pay to ETH Net Chain. Press Transfer at the bottom to get to the Import screen. It will say that the money transfer will take 7-8 minutes. Press Connect at the bottom.

You will be quoted a price for gas to the ETH network.

As for the gas cost, it will be affected by network congestion and other factors, but a gas cost of 2 to 3,000 yen would be inexpensive.

In any case, you need to set your own rules and draw a line where you are willing to pay less than this amount for gas.

As long as the gas cost is acceptable to you, you can connect and remit the money.

After about 7 to 8 minutes, ask the customer to open MetaMask’s Matic Mainnet and if the deposit is confirmed in the ETH section, the process is complete.

Sign and pay on MetaMask!

Once the payment is confirmed in MaticMainnet on MetaMask, you can purchase the NFT work you want. Select MetaMask and you will be asked to sign.

Click on the “Signature” button at the bottom and you will be asked to Check Out.

Summary of how to list and purchase items on Polygon

The following is a summary of how to list and purchase items on Polygon.

  • Using Polygon is recommended for NFT beginners because there are no gas fees.
  • You need to add a network to transfer ETH to Matic, which is a Polygon network. If you don’t bridge the network, you will lose your money.
  • If you want to be recognized by overseas collectors, you should list on the ETH network.

Above. Keep on listing on the Polygon network, where there is no cost!