However, I would not think that the property tax exemption would extend into commercial assets since these are more investments and not your primary residence. 

They are the primary difference between profit and loss for YOU.The PM is just as important as the deal you find, may be more important.

I am a teacher so the part time investing primary in my summers off is how I plan to get started.

If homeowners see their bottom line w these services and with a traditional sale most people will go with the inconvenience of showing their home for a week and being in escrow for a month to keep THOUSANDS of dollars in their pocket.Most homeowners don't know what their home is worth or that it has gone up as drastically as it has over recent years.

What was your criteria for picking your primary residence?

my traditional lender informed me that with my high student loan debt spoiling the debt/income ratio, I only qualify for 175,000 and no more.   

I have 2 rental property and 1 primary home in Southern California.

I have been out fund raising and while I was prepared to handle a primary private lender.

Are they found through traditional channels like Loopnet, or are they off-market?

It decreases after each year but the point of a USDA loan is to live in it as your primary residence.