Borrowing down payment with owner financing - where to start

[Season Price]

Hi. I found a cash flowing, multi family property that I don't want to pass on. The owner is willing to finance 80%, 4% interest rate amortized over 30, with a balloon. I originally had a family member interested in partnering for the down payment, but they have backed out. What are some of my options for the 20%? I am willing to give equity, or 6-8% on a loan. I am in a position where I am debt free, have very little living expenses, and own two homes. However, both of my homes are in non-desirable places, so I can't get a heloc. I am self employed, so a traditional bank is not an option. Are there any private lenders who would consider my situation?