Such a decision is a very personal one since it means losing an animal for which you probably have deep feelings. However, most pet owners will have to occasionally make such very hard decisions since we're not made of endless money. I had to make a decision as to whether to spend $2500 for a risky surgery on a much loved old dog I had. After many tears, I decided not to spend the money since the potential for success was low. My dog died before I could even pick him up that afternoon which justified the decision since it would have been several days before he could have had the operation. Making the decision was incredibly painful. Good luck with your decision and do not feel guilty if you cannot reasonably afford the vet costs. However, if necessary, do seek vet care for humane euthanasia.