Looking to invest in small multi family and need input.

[Gary Mariencheck]

I'm currently putting a plan together to get myself into multi family investing. I've picked two areas here in Memphis close to desirable schools. I can find duplexes, triplexes, and fourplex in both of these areas. My plans is to purchase, over the next 3-4 years, 4 duplexes in the $50k range. I will live in one side with my family while renting the other side. I do however need advice on getting financing on one of these. Based off of a $50k purchase price, was going to put $12,500 down and go for a 15 year mortgage on all of the properties as I acquire them. I understand that cashflow will be a little less. After 4 years my goal is to have 4 duplexes all cash flowing at $3.5k/mo for 7 units. Any input? I'm keeping an open mind?