nancyjac's right! Your insurance co (if you have insurance) would be the first place I'd start. Other than that, I'd try several avenues (off the top of my head) and they include - The American Cancer Society and Cancer Care (which offers stipends to people with cancer having financial difficulties).
You may also wish to hold a fundraiser (there are ways to do this on Facebook) and through your Church, Synagogue, Mosque. There are also grants given to people from certain ethnic communities so it will require a bit of research on your part, but it's not impossible.
Wishing you the best of luck,