Hey OP, I've probably joined 4 or 5 gyms in my lifetime, and only ever stuck with and gotten the full 12 month membership usage out of one, which is Fernwood Women's Health Club. Yes, its probably not the cheapest gym in my area, but the setup, service, facilities and staff are organised in a way that actually make me go and want to go!
So I think price is relative to the type of facilities and services you get, and whether or not you are actually motivated to go!

In answer to your question, basic membership at my Fernwood is about $20-25 a week. My membership includes a weekly Personal Trainer session and is about $50-$60 a week.