Testing a node.js script on mainnet

Question

I have a Node.js script that sells 105 NFTs to the highest bid offers. I have tested the script on testnet but to be 100% sure, I also want to test the script on 105 NFTs on the mainnet. But I do not have any real NFTs. Also, minting my NFTs or buying from Opensea will cost me hundreds of dollars in terms of gas fees.

Is there any way where I can get a real NFT collection with 105 NFTs to work with, without costing too much?

Answer 1

1. Cheaper production networks (not recommended): My assumption is that you mean Ethereum mainnet when you refer to "mainnet" in your question. There are other production networks with significantly cheaper gas prices. There is a downside to this, however as you will have not "proven" that the script works on Eth mainnet.
2. Mainnet forks: most RPC providers (eg Infura, Alchemy) provide a community service which allows devs to fork the state of mainnet at a particular height, along with convenience functions (calls) for manipulating time and other useful things. This provides the full state of Ethereum's mainnet without needing to actually spend real gas on transactions - in the forked state you're able to mint yourself eth, alter state at will, etc. At the same time, it's still the full Ethereum environment. This is generally the suggested way to test that things work on mainnet. (In addition to testnet deployments, which you mention that you've done.)

Hope that helps!