I found a related topic, but it was a few years old, so I wasn't sure if it was outdated. I'd like to open up an art shop but I wasn't completely sure of the sP to USD conversion rate. How much would $2/$3 usd equate to in sP?

There isn't a fixed rate, but $1 = 100 CSC so normally people do the conversion based on how much a 100 Credit Gift Card is in the SS.