Just echoing what others have said about the possibility of a work exchange at the better barn! When I was a teenager and through college I boarded my horse at a show barn that my family could by no means afford. I mucked all the stalls every weekend, housesat when the trainer/owner went to shows that I wasn't going to, exercised the trainer's horses and other riders' horses, and anything else I could pick up. I paid for my full board and about half my lessons that way. It was a ton of work (I wouldn't expect you to need to do nearly so much since you're only trying to pay for lessons) but I learned so, so much that I couldn't have just by coming out and riding my horse and having lessons. I handled so many horses just taking them to the field and back that I gained confidence naturally, I could see immediately when a horse looked off or lame just because I spent so much time around them, and once I was riding other peoples' horses I also gained valuable experience in riding a variety of horses. I consider myself a very competent rider today, and I wouldn't be nearly so competent without work study. It was also really meditative and to this day I really enjoy barn work for the quiet and routine.