How much should I charge as a freelance game tester? More specifically, how much are indie game devs willing to pay a freelance tester with professional QA experience to test their game? Per hour or per day?

I'm a professional game tester and I'm starting my own freelance side business for some extra income, but I don't know how I should price myself. Any feedback on what you're all willing to pay for testers and how much testing you would pay for would be a big help to me.