Generally there are three categories of multifamily investment properties – which will greatly determine your loan options.These three categories are based on the number of units at the property.2-4 Units: While these are “multifamily” properties in the sense that there are “multiple units” – you will generally have very similar options for financing to traditional residential loans on single family rentals – think the traditional 30-year fixed rate conventional option or DSCR Loans – and the coveted 20% down payment option too.

I just sold a duplex for $520,000 in four days, even though the current income is $1800/month and the market rate is only $3,000/month.

My only challenge would be the occupancy rate.

Quote from @Nick Bednarczyk: Reminds me of what we saw in the 80s and 90s when we refied into 5-6% rates when we had the chance. 

Here's a bit more in detail about how rates are calculated for DSCR loans:1.

So this may result in a higher interest rate. 

In the Midwest you can expect to find 2-3.5% cap rates, appreciation makes up for the rest.

Knowing that market rates are in the high 6s at best, and much higher most likely, I would be looking for at least 6% interest. 

interest rates dont affect properties at this price point.

But, these properties are living, breathing and moving things that are all exactly the same, so you should just use your standard assumptions about payment and vacancy rates.