I'm not sure if I can offer you a quick answer, but I do have a couple pricing tips! :)
- Don't lowball yourself. This is real important! Everyone wants art on the cheap, but don't be discouraged - you've earned your money fair and square. It's much easier to start high and slightly lower the price to increase demand than to start low, get swamped in demand, and try and jack the price up to compensate. With low prices, you could be doing a lot of work for an amount of money that just isn't worth it, and you can get burned out fast.
- Sidenote: if, later, you're considering lowering your prices because of low demand, try advertising yourself before doing so. It might not be your prices that are keeping you from getting work - it might just be that potential customers aren't aware that you're selling something.
- For a baseline price, time yourself next time you draw something comparable to what you want to offer as a commission. Work at your regular pace and all, just see how long it takes you. Now you can use the minimum hourly wage to start from... but you probably don't want to work for minimum wage, so raise that price until you're comfortable!
- For example, if it takes you an hour and a half to draw two characters from the waist up, and minimum wage is $7.25, that's an absolute minimum of around $11 for that commission type. You'd probably want to raise the price from there, but definitely don't lower it, or you're working for under minimum wage!
Pricing is really about how important your time is to you - when you're drawing a commission, that's time you can't spend doing anything else. If a slightly-animated fullbody drawing takes you two hours, how much would someone have to pay you to buy two hours of your time?
Hope this helps! Good luck with pricing!