To be honest, way too much. I think it was around $40-50 for an hour, but I found it worth while. I only saw her once or twice a month though. She is a qualified and experienced teacher though, so I think that's why she charged so much. I know she also does cheaper (maybe $25 an hour) skype lessons.
The second tutor charges $25 an hour, but I don't have any first hand experience with her so can't vouch for her quality.
The big thing to consider is that in a one hour group lesson the teacher will be talking for half the time, and the rest of the time will be divided up between the rest of the class mumbling through sentences. That means you might only get 5 minutes of speaking time / teacher attention throughout the entire lesson which I don't think is anywhere near value for money.
Check out these websites which would offer a way cheaper alt. I don't really dig them because I think it's hard to learn through a webcam/keyboard, but they are popular for a reason.