It depends on what you want to get out of the coaching. If you feel like you've learned everything you need to know, sure, stop. One example I can think of is driving your car. If all you want is to be able to get a license to drive a car, once your driving instructor shows you how to do it and you get your license, you certainly wouldn't go back to the driving instructor for further lessons. However, if you want to progress to driving a race car, you will need to continue with the driving lessons. It may not be with the same driving instructor but you will still need further lessons nonetheless.
If your coach is any good, I think most people here will agree that you have an excellent deal paying $10/hr. You really don't have to have a regular session with your coach. You can arrange it so you only go to him when you need to learn specific things. You will know what to learn as you play against other people. If having people to play with is a problem you might want to ask your coach if he has students who might be interested in playing with you.