I see a lot of artists underpricing their refsheets.
So what if ref sheet commissions weren't a thing?

Commission the art that goes on the refsheet, and assemble it in Google Drawings like a moodboard. Replace art as you have stuff you think represents your character better.

And most artists out there I bet would appreciate a turnaround commission here, a few headshot sketches there, a flat color illustration another month, way better than one big half-priced (or less) chunk.