J.J.
If you want something affordable, you may want to consider hiring an older teenager to teach your son. When my son was 11, he wanted to play drums, and that is what we did. It worked out GREAT! He got some good instruction at a very affordable price. We didn't want to spend a lot on something that may not have lasted.......
Now over six years later, he is still a BIG drummer and in a small band. Hiring that teenager to teach my son was the best thing we ever did! And, teenagers are always looking for ways to earn money - especially doing something they love!