Not sure the price, but I do know that when my friend talked to her vet about doing that to her TB that couldn't keep weight on him, the vet said that it is not always accurate and she would be best off to treat him for ulcers even though she wasn't positive. If it helps, then he has them, if it doesn't, the medicine or whatever she ended up using would not hurt him
But I am not vet so I don't know if that is particually true
I had my horse receive endoscopy a week and a half ago to confirm that he did have stomach ulcers. I can't remember the exact costs right now, but I have the bill up at the barn so I will post back here in a few hours. The annoying part of endoscopy is the horse can't eat for 16 hours before, which often aggravates the stomach lining even more. I guess that is a necessary evil. From what I remember, the price killer isn't the endoscopy, it is the ulcer treatment. Treatment is 28 days of Gastrogard (administered once daily) and is about $950. After this 28 days, my horse will be again receive endoscopy to see if the ulcers are gone. Once again, I will report back after I go to the barn for the exact pricing for the procedure.