Conventional financing mimimum loan amount?

[Marc Steinert]

I was originally preapproved for a conventional loan with 20-25% down. Since, I have found an REO that I'd like to make an offer on with an asking price of 50k. There has been no movement on this property and the listing agent has divulged that the bank is negotiable so I wanted to come in with an offer around 30-35k, but now my mortgage broker is telling me she cant finance anything less than 70k! This is a rental property not a flip, any advice?