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How to buy, sell and create NFTs on OpenSea. The ultimate guide

Many people were betting that the NFT bubble would end in 2022, but as the data shows, this is not the case. On the contrary, volumes are growing and even big companies like H&M, Square Enix or Samsung are starting to enter the metaverse and non-fungible token sector. This is why The Cryptonomist, at the forefront of the creation of its collections such as The NFT Magazine and Cryppo, has decided to draw up a detailed guide on how to use OpenSea, showing the various steps for buying, selling and creating NFTs.

The guide is authored by Alfredo de Candia, author of the book Mastering NFTs – A Practical Guide for Beginners and Non-Beginners (book also available in NFT format), which contains further guides on the whole process and various blockchains.

The guide for OpenSea focuses on creating NFTs on the Ethereum network (ETH), showing all the steps and how the famous gas cost works.

What to do before starting to create an NFT on OpenSea

The first step is not to rush to the OpenSea platform, but to MetaMask or Eidoo, as we need a wallet that can interact with the Ethereum blockchain.

Here is the guide to using MetaMask.

Now that we have our wallet, we can proceed with the next step, which is to buy ETH, essential to pay the cost of the various transactions that we are going to make.

How much Ethereum should I buy?

This depends a lot on how many collections and NFTs we need to create as the average cost for a transaction on Ethereum is around $100 plus the transaction for the new collection which is around $300. Note: these figures are variable and depend on both the price of ETH and the congestion of the Ethereum network.

Where to buy ETH?

All cryptocurrencies can be bought via so-called crypto exchanges, both centralized (CEX) and decentralized (DEX). Both MetaMask and Eidoo offer the possibility to buy crypto from the wallet itself using a bank transfer or credit/debit card.

Now it is finally time to go to OpenSea and login with MetaMask or Wallet Connect if we use Eidoo.

Metamask Opensea
How to connect Metamask to Opensea

Then we have to select our Ethereum address to which we want to connect OpenSea and confirm the connection by pressing “Connect”.

Metamask Opensea
Select the Ethereum address

How to buy NFTs

First, let’s look at the procedure to buy an NFT. The first thing we need to do is to find an NFT that we are interested in or a collection. In our case, we choose the Cryppo collection, the official collection created by The Cryptonomist and then we choose the NFT we want to buy.

On the next screen we can see all the details of the NFT and also how much it costs, and in our case this NFT costs 0.05 ETH.

At this point we have two options to buy the relevant NFT:

  • we can click the “Buy now” button buying at a fixed price, in this case because we buy directly from the seller, 
  • we can make an offer for an NFT already in the possession of a user.

To make the offer we have to click the “Make offer” button and in the next window we have to select and accept the disclaimer.

On the next screen, if we want to make the offer, we must first convert the ETH to wETH. In this case, simply click the “Convert ETH” button and confirm the transaction by entering both the price in wETH we want to offer and a deadline for our offer.

Once we have entered all the data, click on the “Convert ETH” button.

Cryppo Opensea
Select the NFT collection to purchase
Opensea offer
Make an offer on Opensea

On the next screen we need to convert our ETH to wETH via the UniSwap platform, so just enter the total ETH above and the wETH below. After that we have to click the button and confirm the transaction on MetaMask or Eidoo, which in our case costs just over $15.

Convert ETH to WETH

Only then can we go back and complete the transaction by clicking on the “Make Offer” button and confirm the transaction again which will allow us to buy the NFT if the seller accepts our offer in the given time.

If we want to buy it directly, we have to click on “Buy Now” and confirm that we have read the disclaimer. Then the screen will open with the total amount of the NFT and other details, such as the royalties of the NFT, and then just click on the “Confirm checkout” button and confirm the transaction with MetaMask or Eidoo. 

Opensea checkout
Checkout completed

How to sell an NFT on OpenSea

In case we already have an NFT in our wallet and we want to sell it, then the procedure is different.

First, we have to enter our profile in the top right corner.

sell on Opensea
Select the user profile

Now choose the NFT we want to sell and click on the 3 dots at the bottom left of the NFT. 

This will open a small menu where we will find the item “Sell” to proceed to the next screen:

sell on Opensea

sell on Opensea

The next screen is quite intuitive: first of all we will have to choose if we want to sell our NFT at a fixed price, or if we want to make a time auction; then we will have to insert the price in ETH.

If we set it too low compared to the floor price (the average price), OpenSea will warn us and will recommend the minimum price at which to sell.

Finally, the duration of the sale must be chosen. In addition, in the “more options” section we can also choose whether to bundle our NFTs or sell them one at a time, and choose whether to limit the sale to a specific address/user.

Finally, we click on the “Complete listing” button and confirm the transaction from MetaMask or Eidoo:

sell on Opensea
sell on Opensea

How to create an NFT

Let’s get to the juiciest part of the article, how to create an NFT on OpenSea.

First of all, after logging into OpenSea with our wallet, we need to click the “Create” button in the top right corner, and then sign the transaction with MetaMask (this signature is not paid).

Create NFT on Opensea
Create NFT on Opensea

On the next screen we have to insert our multimedia file (this can be an image, a video, an audio and so on, but a maximum of 100 MB).

Next, we need to enter the name, a link to our site or our social media, a short description and then finally other information such as unlockable content, the number of NFTs to create, the blockchain of reference.

Finally, we have to click on the “Create” button and confirm the transaction, which again will cost nothing.

In fact, by doing so, we have only created the NFT but it is not listed and therefore we have to go to the step before and follow the procedure for the listing of the NFT, paying the cost of gas for the individual NFTs that we want to list on the OpenSea marketplace.

Finally, there is a way to pay less fee on OpenSea which is to take advantage of the Polygon network (MATIC).

In this case, you have to add the Polygon network to MetaMask, and then you have to buy the MATIC token.

To conclude, here’s a bonus tip: if you want to estimate the value of your NFT or that of other users (on the environmental impact side), you can use a dedicated application, NFT Estimator, which allows you to value an NFT according to the blockchain of reference, 7 different blockchains.

Collect writing NFT

Alfredo de Candia
Alfredo de Candia
Android developer for over 8 years with a dozen of developed apps, Alfredo at age 21 has climbed Mount Fuji following the saying: "He who climbs Mount Fuji once in his life is a wise man, who climbs him twice is a Crazy". Among his app we find a Japanese database, a spam and virus database, the most complete database on Anime and Manga series birthdays and a shitcoin database. Sunday Miner, Alfredo has a passion for crypto and is a fan of EOS.