It depends on where the golf course is located, and the quality of the course. $20 isn't bad for a cart....
If you're talking about a typical suburbia golf course.. that's much more than usual...
If you're talking about a beautiful golf course, in a "vacation paradise" i.e. Hawaii, then that's not too bad of a price. In vacation/resort areas, it's a case of supply and demand.... only so many people can play at a time.... So, on one hand, it's great to live in an area that everyone else only gets to see on vacation... On the other hand, sucks to be you, if you're an avid golfer.