I have a cat who gets urinary blockages because of crystals. My vet said they are struvite crystals. My cat is 5 and I control this with meds and diet. So far, so good. I was told by her that when cats get older, they can develop calcuim stones in their bladder, so it's not uncommon. I would let my cat have the surgery and talk to your vet about making payments. My vet was fine with that. My Ming's condition can run me a thousand dollars every time it flares up and there is no way I could pay that or more at one time. Most vets have that sign in their office that says you have to pay at the time of service, but if it is a large amount, most will work with you. After your cat's surgery, follow whatever the vet says to do. That is the best way to keep them healthy.