I have a cat. I've gone into a huge amount of debt to pay for her medical care but there has to be a limit. I would guess something around $8,000 but it really depends on what their quality of life will be and if it is a chronic or onetime cost. (San Francisco, CA)
I had a cat. She was a wonderful companion for many years. She recently fell ill and I spent $2000 before I realized it was her time (the next day) and I had her put to sleep. (Pinole, CA)
A dog. A lot. Thousands. Depends on the outcome and the age of my dog at the time. The chances of her (always a female) ability to recover well too. Difficult. I always love my dogs. (Chicago, IL)