Adopted a cat - may not be able to afford it in the long term - what to do?

Actually I'm in somewhat of the same place as you. I have a disabled cat (he cant walk very well...at all) and we could get it all fixed but it would cost ALOT. I don't want him to keep falling down and getting hurt...so I actually did the best thing I could do for him, I called a vet a had talked too awhile ago who said that if i couldn't take care of him that he would take him, he can do all the treatments and all that but I've grown so attached to my cat and he has with me. I know he would be so much happier if he could walk but I don't want him to think I just gave him away. Sometimes you have to do whats best for them even if they wont totally understand, be sure to give him lots of love and maybe when your all caught up with everything you can get him back...