Most of the delayed-release oral ASA5 medications for uc (Asacol HD, Lialda, and so forth) are ridiculously expensive. Colazal (balsalazide disodium) is an ASA5 that doesn't have the expensive delayed-release coating so I think it is cheaper than Asacol HD but still pretty expensive. Some of the drug manufacturers do have assistance programs if you cannot afford the medications and meet certain financial requirements (e.g.,
Patient Assistance for Lialda).
Sulfazine is a much older drug used to treat uc and it is much cheaper than the aforementioned ASA5 meds. It does have more side effects than the ASA5's which is something you should research. There are a number of people here on HW who use Sulfazine and have no issues with it. I think it costs less than $100 a month.