I'm not sure what the going rate for hookah is but this place seemed pretty reasonable to me. We had one refill and the price was a tad over $20.
Service was decent too. We were asked a few times if we needed a refill and when we said yes, it took about 10 minutes.
The place isn't kept very clean though. Gross bathroom too. I'll call it one step above a gas station bathroom. Not sure why another review was raving about it.