I pay £30 (UK) per hour [which is about 42.5 dollars according to an online converter I found), and its worth every penny.
Do you have just the half hour? I used to share my hour with my daughter (1/2 each) and it was not nearly enough. When she dropped out & I took the whole hour there was an exponential rise in my rate of improvement. I do roughly 1/2 an hour of exercises & warm-ups, and then 1/2 an hour of working on particular songs.

Kris