Should I spend $500 to get my cat's teeth cleaned?

My wife took our cat to the vet for a checkup and weight check (when we got her she was grossly overweight and has been on a diet). The vet said that she had moderate tooth problems. I forget the stages but on a scale of 1–4, 4 being the worst, our cat was like a 2. But the vet also said that to get it fixed it’d cost over $500—and that’s if they don’t have to do anything else. Anybody else have experience with this?