Conventional lenders are going to cap the seller paying the buyers cost @2-3%As a buyer it is more beneficial to pay a slightly higher sales price with your closing costs covered by the seller becasuse the actual cash you need to close the deal will be lower.

If it includes all expenses then you have some positive cash flow, a 15% cap rate and $12,000 of paydown of principal. 

I've got a basic calculator that I've built that helps me determin roughly my monthly/annual payments and income and is currently capped at 10 units. 

Was talking about that just last month in a Multifamily Executive piece Cap Rate Limbo: How Low Can They Go?.

Putting cap rates and ROI aside, almost anybody can hit those numbers with cash all-in and no debt service.  

I am looking to know what areas are good to invest in and what areas can get me a 8 or 9 cap.

Although most places put the cap at renting to no more than 4 people.

Forgive me for pushing this further, but you do not believe there is any market in United States where you can buy and hold a property in the long run for decent cash flow (8-9% CAP)?

., Cap rate....s,   are 2-4 times better that what I am typically seeing in my area. 

Other than that, if your goal is to buy something that is more or less turnkey or is at its peak as far as value and use, you will probably need 15% at minimum, but most conventional lenders will cap you at 20% down for SFR's and 25% down for 2-4 units as was stated in a previous post.What is your goal?