Depending on your vet, it doesn't NEED to cost that much. He's probably going to suggest GastroGard, which is the BEST ulcer treatment out there and works wonders, but it's not the only method. And you won't have to give him that much EVERY month. Just until they go away and then maybe part of a tube when he is traveling/showing/etc.
My mare had ulcers in December and was all cleared up for $80. She wasn't scoped either. I called my vet because she was suddenly a total jerk and went to cowkick me when I touched her belly. She was eating fine and everything. Those and a puffed up belly were her only symptoms. My vet and I agreed ulcers seemed like the culprit, so she used acupuncture to determine it because the clinic is over an hour's drive away and I don't have a trailer. But scoping is the best way to go.
Ask your vet about Draw if you can. It's meant to be a cleaning solution for exterior wounds, but the main ingredient is magnesium and works very well to heal up ulcers. That's what my vet gave me. She got 60ccs twice a day in grain. Cleared up in a month, like most other medications. She's back to normal now.
First, is he stalled and grained? If yes, I would put him outside if possible with as much hay as he can fill his face full of.
If he does have ulcers, U-Gard is really good to give after to prevent them from coming back. My BO said it takes about 3 months to take full effect, but they use it on their show horses and works awesome. Abby's being started on it as soon as I get it next week.