There are cheaper options then our vet and we were thinking about it for Ray, my avatar, who we adopted when he appeared at a campground and we were told he had been abandoned there 3 months prior.
It cost us about $350 to fix him, get 5 stitches in his shoulder from 1 wound, have the pus filled chest wound cleaned, have him wormed, get tested for feu-leuk and also get all the shots, since he hadn't been fixed we figured he'd never been vaccinated. After finding all the problems we were really glad we HAD taken him to our regular vet, since I don't know how the cheaper clinic would have dealt with the other problems.
And they did give us a discount for rescuing a stray. I think you could probably find a cheaper vet for sure. When we were on the road with our last cat who needed to be put to sleep, one of the vets I called insisted on doing a $200 physical himself, even tho we had the paperwork from 2 other vets we'd taken him to on the trip...no thanks, we knew it was time. Another vet just put him to sleep....thankfully so he did have to suffer.