Co-signer fee

[Jonathan Alexander]

I've got a cash investor willing to put up money for a down payment of 20-25 percent or more but doesn't want to put his name on a note. My debt to income ratio isn't good enough to to get me qualified for an additional rental property (I already have one property).  

From what I've been told my only recourse to get an additional mortgage is to get a co-signer. If I were to get one and all they'd do is sign the note with me, what would be fair compensation for them. My ide would be to refinance them off the note asap. Any feedback would be great. Thanks.