Oh, honey, do I ever know what you're going through! I've had my share of poverty, and problems making ends meet...it's so hard. You hang in there, and try to make it until pay day!!! Call everyone, and set up payment arrangements...this way, they'll know you're making an effort.
The truth is, you need to find a vet who will make financial arrangements with you. This poor kitty needs some help immediately, and I'm afraid that she won't make it, and you'll have to live with some serious guilt...there's always someone out there that will help your kitty, and you!
In the meantime, we've got to find a way to make her eat. If she's refusing all food, my gut instinct is telling me that she's first of all very dehydrated...a dehydrated cat will not eat. If you have some low-salt chicken broth (or soup broth, bouillion cubes, whatever) on hand, syringe feed her that slowly, diluted in some water (about 50/50). If you have a blender, puree some cooked cold rice, chicken, and broth together, or dilute baby meat with water and plain yogurt, and syringe feed her. You've got to force her. Wrap her up in a towel snugly, so she can't back up out of your grasp, and lay her on your lap, tummy down, not belly up. After the food has made it somewhat into her mouth, close her jaw, and rub her throat to encourage her to swallow. Do this until you can get about 1/4 cup of food into her...even if it takes you an hour and a half. Make sure she's warm enough, and monitor her use of her litter box. If she's straining to go potty, or is having accidents, howls in pain during urination or during a BM, you must get her to the vet, ASAP!
Please let us know how she's doing. I'm very worried for you both.