Appropriate​ interest for your cash lendors

[John Valley]

I was wondering what the appropriate amount of interest a cash lender should receive on real estate purchases. I am a first time buyer and found a great 3 unit multifamily apartment building that I want to purchase. The unit is generating over $3,600 in gross income monthly with low expenses. However, I am low on cash for the down payment of about $45,000. The home is going for $250,000. I may have a potential investor that could lend me the $45k. How much should he receive in return, and how often should I repay? Lump sum? Monthly?

Any advice would be much appreciated!

Thanks