So how exactly is the "gas money" calculated? I was led to believe it was expensive because putting all that data into the blockchain costed a significant amount.

Asking because, wanting to verify whether NFTs were really a scam or scheme instead of just following heated Twitter arguments, I looked into uploading my own NFT. Gas money for a single image was $250--estimated earnings for an NFT are in the low dollars for most people, so it certainly wasn't worth it for me. I told a friend how insane the price was and went back to attempt the process once more a few minutes later to get a screenshot showing him I wasn't lying--gas money for the same image was suddenly over $800.

I can't think of any reasonable way to justify such costs if it's just encoding a few bytes of text and not an actual image, so now I'm doubly suspicious of how these costs are actually calculated. It reminds me of countless other schemes where you put in a bunch of initial cash to "start your own business", then spend the rest of your days desperately trying to find buyers.