aww poor kitty. I'm so sorry she is going through this. I think she may have anything from sinus infection to nasal cancer (this one is very serious). Nasal polyp is also a possibility, foreign body in the nasal cavity or a serious tooth problem.
According to Susan Leck, a DVM who has seen cases like this before, if the teeth are bad, they can be cleaned and pulled if necessary. A nasal or sinus flush may be needed, and xrays of the sinuses are a must. Your cat will have to be sedated for these procedures, and at the age of 8 I would recommend doing some bloodwork (liver and kidney tests) to be sure that his internal organs are functioning well before sedation. I personally don't think there is any other way to know what her problem is really. I'd ask another vet, see if they accept payment plans. There are low cost vets in some areas so you can always google that. Sorry I'm not being of much help. I wish there was another way to treat this, but without tests it is impossible.
Good luck, and please let us know what you find out.
A less serious (usually) possibility is allergies. Has she been tested/treated for allergies? Sometimes products we use around the house can cause reactions in our pets.
Whatever the situation, prettykitty is right - tests are necessary. If you live in or near a city there are usually quite a few options for low cost vet care. If nothing else, you can call your local aspca and ask for advice.
Keep us posted, please.