Seller financed (probably) won't be reported to the credit bureaus and so won't impact your credit score at all.

Typically 75% of rental income can be applied towards your DTI for qualification. 

It is easy for people to download fake W2s, ESA paperwork, etc, with a few mouse clicks and a credit card. 

@Donald Hatter We send the information to a collection agency who attempts to recover the money; after they make several attempts they place it on their credit report. 

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.  

WE dont pay a fee for the credit line as I mentioned just 1/2 point for each new loan..

You could, for the purposes of verifying that you are not renting to someone who is potentially dangerous or financially incapable of shouldering the burden of being a roommate, ask them to apply through Zillow so that you can see their background check, that also gives you the opportunity to have others who might be interested in being your roommate as well, apply.

Credit cards have the same limitation on the amount you can borrow and will likely end up costing more than private lenders.

The sub 550 credit score people come out of the woodwork to apply for this home. 

If they only make $2000 and know their income has to be $3000 or higher to qualify, they can apply elsewhere and save the $30 application fee.