Fee Structure in Layman’s Terms?

I wrote an algorithm for trading crypto and I’m trying to understand Solana’s fee structure. I went to trade my $2.50 worth of Soulja Coin for PUPPY today and the fee was $0.91 worth of SOL. That’s almost half the value of the coin I was trying to trade. Is this just a scale thing? Like would it be a lot less relatively if I were trading $2,500 dollars worth of Soulja Coin? Or would the fee be $900? Hopefully my question makes sense, I was just hoping someone could explain the fee structure in simple terms or direct me somewhere that explains it, because so far what I have found on YouTube is very confusing and contains too much information.

TL;DR If I am day-trading only crypto on Solana’s network, how can I prepare for fees? If my algorithm tells me to trade a given coin, how do I know how much I can expect to pay in fees without initiating the transaction?

In the simplest terms: How does the fee structure work for coins on the Solana Network?