Check craigslist in tour area to get an idea of what people are charging. Some have their own gyms others will train you at home, your gym or the gym they belong to.
For the last year I was paying $300 a week for 4 one hour sessions. Not sure if I was overpaying a lot or not but this guy was the only local guy who had his own personal gym. I stopped going after about a year because by that time I had figured out the whole routine and food thing. Now I can just do it on my own. Besides it saves me some money.