My normal balls are probably not worth much more than say $50. I have definitely spent more than that on food and husbandry, so would I drop money on vet bills over $50? Of course.

That being said, there is a point where I believe it gets excessive.

When I was younger we had a cat named Simon... he was a purebred Burmese, and also the nicest, sweetest cat in the world. I loved him dearly. One day my mom found a lump on his belly, and it turned out to be lymphoma. He was only ten years old, which I'd say is "middle aged" for a cat. Now my mom, she would not let me or my dad have a say in anything. She dropped thousands of dollars on vet bills for him. I was only 11 at the time. What happened was that Simon turned into a zombie from the chemotherapy, and we watched him suffer and slowly fade away. Finally when things were looking far too bleak, my mom decided to have him euthanized. She would not even let me come with her. Honestly, I know she was distraught over his being sick. But I really think she was clinging to something that just was not going to happen. Even at 11, I could see early on that he was not improving at all from the treatment.

Would I drop significant amounts of my money on vet bills for an animal? No. I will pay up to what I feel is a reasonable extent. Anything past that and it is a quality of life issue - if they are really suffering, then I would choose to put them to sleep. I agree with Frankykeno that animals are NOT people... obviously if the question were rewritten to "Would you spend beyond your means on medical bills for a beloved family member or friend", that would be a no-brainer.