Depends on the tests that have to be done and at what point the crystals are. For example with our guy last year, he was almost at complete blockage and therefore needed more aggressive measures. A few years before that he had a small case where all we had to do was a small reg of meds and different food for a bit.Sounds like that vet scammed you. I paid like $280 for urine and blood tests on my cat... when he had a crystal, they said I could spend $1200-1500 to have them remove it or put him on meds for like $400. Took the $400 option and changed his food to urinary control. No issues after that.
This time around it cost so much since we had to get the full x-ray and blood/urine tests to find out what was wrong. But I will say there can be big differences in prices between vets.