At 13, unless he's SERIOUSLY good, you'll find the courses expensive at a little too demanding. A much better option, IMHO, is the 9 hole walking course Oak Hill Trail. It's a bit shorter per hole and only a couple of carries over water. It's also a good deal cheaper than the championship courses. Yes you can hire clubs at all WDW courses, on the 18s you get a full set, on the 9 you can rent just a half set.
The championship courses vary depending on the season, but generally you're looking in the range of $100+ ( and that's playing twilight rate). I think Oak Hill trail is about $25-30 not sure on the cost of clubs but junior clubs will be cheaper than adult. You can find all the prices on Disney's own website.