Since the word is that Peyton wont play in the NFC, that means we will most likely be facing Brady and Manning 4 times a year. Thats a quarter of the schedule right there and not amusing at all.
Mario Williams might be the best way to counter Peyton going to Miami. (other than signing him ourselves of course)
But as far as financially speaking... well thats a different story. I still dont believe its doable unless its the only free agent signing the Bills do. (Even then, regardless of the money, Williams will have the final say.)