Vets are very expensive.
I know, Luckily for the pets of poorer folk in the UK, we have a charity called the PDSA (Peoples Dispensary for Sick Animals) where you just make a voluntary donation , of whatever you can afford. I don't think I could ever have afforded to keep cats otherwise. At least not responsibly. Even so, i never actually set out to take on a cat, just fell in with my partner's ingrained cat habit, and cast my vote in favour of adopting a couple of strays when they showed up at our door (it's amazing how they recognise a sucker isn't it?)
Being veggie, I never felt comfortable with feeding them that canned kangaroo or whatever it is, though
Wouldn't keep them again, for that reason alone.