Chiming in, I think two hours is reasonable for a single 8x10 from entering the darkroom to hanging the print to dry. Once you get a print you like into the stop bath, dupes take a LOT less time, so you could probably have ten identicals done in 2h30 assuming no snags.

Remember to pay yourself first.
Figure out what two hours of your time is worth to YOU, without consideration to what's affordable or competitive.
THEN figure out your costs,
THEN figure out what price the market will bear.
At that point you can adjust what you're getting paid if it's worth it to you.

You pay yourself first for two reasons: you need to make sure that the thing is financially feasible, IE if the price you can charge is less than what your time is worth the project needs to be re-engineered,
and if you aren't getting compensated sufficiently for your time you will grow to hate your work, even if the activities of it are things you love. And that's the worst.

Monetizing your passion/hobby is a tricky thing, because if you do it wrong you can destroy something you love.