Looking for opinions about this SFR deal ...

[Robert Del Rosario]

1990 Manufactured SFR (1248 sq.ft)
3 bed / 2 bath

$49,900 asking
$31k~ comps (only a couple sold in the past year like this property)

$800/mo in rent (Lease ends 9/30/13)

Owner willing to carry 15 year fixed at 5% and balloon after 1 year with 20% down.

I have bad credit.

Planning on offering $39k with said terms. Getting an appraisal, inspection, and checking out tenant in DD and adjusting price when necessary.

Little bit worried about the balloon payment. If I have bad credit, how difficult would it be to find a lender on this? How are appraisals with Manufactured homes?