Quote from @Carlyn Chism:I agree with Chris on a lender that might be a scam or make you may so much money interest because of the low credit score that you make $1.00 on the flip or no money.  

Home Equity Loan (HEL) or Home Equity Line of Credit (HELOC) – You could tap into the $150,000 in equity to secure a $30,000 loan.

I would pay them separately rather than giving a rent credit.

Caution:  Personal credit card financing is a huge risk and good luck finding 0 percent interest today.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

The goal of a HELOC is a quick line of credit to either refinance or sell and pay back the HELOC as soon as possible.PS - I would recommend taking a look into the Columbus Ohio market, there's tons of 1% rule deals still within the 120-180k price point with amazing appreciation potential.

Most credit issues can be addressed in some way.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Letters, post cards even calls are useless to this owner class. 

intrest free credit cards and cash How did you add value to the deal?