$40 PS full-body.
How many hours (including the sketch and revision time) does that take you?
2 hours would be a good-ish income, $20/h.
4 hours would be a pretty low income, $10/h.

Other artists use similar hourly-rates, $20~$40. It really depends on how much time you spend thinking/sketching/revising each piece of art, though. Don't sell yourself short. Earn at least minimum wage.

You're like 50% cheaper than most people so I don't think anyone would be upset if you raised it a few bucks

I don't do art but do handyman work. If you're having no trouble finding work at your current pace and your current price, you could increase. But may need to communicate the value you bring to justify.

Your prices appear to be roughly right, but it depends on if you create art as a main source of income, or as a side hustle. If you have a full plate then raise em, if not, keep your prices the same.

HONEYYY, WE HAVE TO EATTT

Your prices are lower than many other artists' for sure. Based on your level of skill I'd say it would be reasonable to raise prices.