At 13u your kid really just needs quality reps and/or competitive mound time. However, this is starting to be the time he needs to join up with a larger organization. As a general statement, they can offer more in the terms of training and coaching. Real talent will usually start to distance themselves at this time and generally by 15 you get a good feel for who the players are. Another option for 1 off youth teams is being absorbed into a larger organization. Discounts and savings can be negotiated if you bring a whole team aboard (especially if that team contains some really good players). Some organizations actually rely on this and become very competitive at 13u.
We did this with my older son's team right around the same age as your kid, and it has worked out for us. However, we also spent a lot of time talking with various organizations to make sure that we picked the best option (includes reputation, coaching, training programs, facilities, past success, PRICE, etc....) To be completely honest with you, the program that we went with was the only one to directly ask us "What can we do to help your kids?"
Buyer beware - It is OK to say "No thank you"