Do you go to a gym?
If you go to a gym, I'd go there during normal hours when the personal trainers are there (afternoons/evenings) and watch them with their clients. If they happen to be free, you might want to just talk to them.
Things you might want to ask them is about their philosophy towards training. I'd avoid trainers that rely on machines.
Rates vary, I've seen them go from $45 to $120/hour.
You can't out-exercise poor eating habits.