If you're not sure how to price something, a commission auction is a great place to start!
Before I ever made an art shop I did commission and YCH auctions and they're a good way to see what people are happy to spend.
I'd usually start with a low SB [starting bid] at 100 or 500 mush, have a MI [minimum increase] of 100 mush and then whatever AB [autobuy] you feel comfortable with! You don't have to include an AB if you don't want to, but I find auctions with ABs typically tend to do better.
As you haven't done commissions in a while, I'd do an auction for a commission piece, include a few examples of recent work and maybe place an AB at 10 apples and see how it does?
The key to auctions is advertising a lot, especially if people haven't seen a lot of your art before!