I would say it has to depend on the contract. I know last year isn't this year but Dalton and Fitz both had 1yr/10m contracts. Mariota was 1/3.5m which I think would be a good price.
Also, not saying he wouldn't go back on his word to be back in Buffalo, but I believe Fitz said he wasn't interested in signing with a team he played for before. I don't have the direct quote but have seen others reference it on TBD before.