There are 4 major ways to look at how much a unit can rent for in the DC area, all with widely drastic rent amounts.1) Market Rate Rent2) Section 8 Rent3) Rent By the Room4) Corporate Rental.Each will yield a different rental amount, and will have pluses and minuses based on the specific location.Just as an example, in Kingman Park on a rowhouse, you might get $4,000 a month in a Market Rate Rental, but $5,757 on a section 8 rental on the same house.

If you qualify for conventional lending then your options are wide open.If your friend does not have it listed and it is at market value, you could at least ask him to drop the price by the amount he would be paying in agent fees if he did have to list it. 

Please note that I'm not talking about comparing these properties to some larger market-wide criteria, only to the ones under consideration at the time.I'll reiterate once more my statement that a cap rate is just a mathematical formula and if it helps you to use it, why not?

I just don't want to be down at Duke's enjoying a Longboard ale and hear some yahoo from Podunk yammering about how he sold his grandma's double wide at a 12.5 cap!

Not to mention they could have a wide range of retail values.

Most of our vacancies last year, by a wide margin were owned by investors with more than one property.  

But with bigger deals, it’s easier to lose sight of the actual deal, because the proformas get more complicated, data is less widely available, etc.  

Look for wide brim felt hats and bearded men with bald fade haircuts.  

@Walter FabiszewskiAfter being a tenant myself for 10 years, in 2009 I bought a single wide for 10,000 and put it on a lot in the country for $100/mo and lived cheap.

A technique I have seen but not used personally is this:Get a set of thin strips of plywood -- maybe an inch wide and one-fourth of an inch thick.