Agree with Minkeybox, when I first qualified I never did any for free, even if it was on models, friends or family I still charged a small fee (I think it was £15) and everyone was more than happy to pay this as they were still getting a treatment out of it.
For clients, I did an introductory price of £30 for a 'limited time only' which I later increased to £40, and then eventually to £45 a few months later. It's definitely a good idea to do some research to see what other people are charging in your area, however, don't ever feel like you have to base your prices on anyone else. No matter what others are charging near me, ultimately I charge what I feel the treatment and experience is worth.