I'm a returning player that hasn't played in probably 15ish years so I have no idea what art goes for these days, any help would be great :)

I only have very old examples, sorry!

Whoa. :o Overlays typically go for $20-60, depending on the artist as well as what you can do (like if you can do steamwork pets, anything with complicated details etc). In sPs/CSC terms, I'd say asking for 2k CSC / 200mil sPs isn't unreasonable for your art! In fact I'd even hit you up for two overlays if you need some new examples~ ;D