Seller finance w/rent 20% below market

[Shane Burke]

Running numbers on a quadplex (this would be my 1st property) a 2…2b1b & 2...1b1b via seller finance. All 4 units are rented month to month right now!  Rents are at $500 on all 4 units… market rents are  average $700…. 3 of the 4 tenants have been there for years!  I would increase rents slowly.  Should I ask only to make principal payments for a few months or take the small cash flow $70 a month till I can get the rents up??