Kidney stones or bladder stones? I would suggest apple cider vinegar therapy with bladder stones, but kidney stones are another issue. And, the apple cider vinegar really should be organic unfiltered, but do the best you can. Real cranberry juice can be helpful (not the sugared, Ocean Spray stuff), but usually before the problem starts. You can also add a little baking soda to the vinegar or mix in with food. And speaking of food, if you are feeding dry then you are seeing the expensive effects of it. Get your cat on a wet food diet as dry diets are notorious for causing kidney and bladder issues. Get some bottled water as the chlorine and fluoride in public water will stress kidneys and bladder function and are often considered a contributing factor of bladder and kidney issues in humans as well as pets.
I've also included a link you might find helpful.
Call your local shelters, the SPCA, PAWS and vets and tell them you have just been laid off. Many shelters will work with you for low-to-not cost vet care when a pet owner has fallen on hard financial times (better to keep the cat in a home instead of it being dumped at a shelter).
Good luck. And if you don't see improvement in a few days, please start making the calls to vets, shelters, and other organization that might be able to help out. Hope you get your job back soon.
***If I see one more "if you can't afford a pet, get it a new home," when someone has been screwed by the economy I am going to scream. Yeah, and like the people are lined up waiting to adopt all these animals. Not! ***