It's a strategy allowing you to defer capital gains tax when you sell a property and reinvest the proceeds into another 'like-kind' property.

They grow in value, the tenants pay down mortgages increasing equity, you get tax benefits, and there's the appreciation. 

Say you bought it for $200,000 and sold it for $250,000 and they put $50,000 down.Your basis is now $150,000 and the principal payments that come in from the borrower will continue to lower your basis and the interest payment is taxed at ordinary income rates.

They get no upside but are downside protected because if you did not pay him he could foreclose on the property to collect what is owed.

Even with $0 down I may be able to cover the mortgage with BAH from the military but then I'm concerned about all the other costs (CAPEX, PM costs, regular maintenance, taxes, etc.).

Tenant could not pay taxes and had to give him a break on rent. 

Landlord friendly, low taxes, job growth, and close to all the recreation of lake Tahoe. 

You’d owe 15% on the$150k gain (22,5k) plus 4 years of depreciation recapture at 25% ($7k?).  

Where does everyone find taxes, vacancy rates, expenses, etc.

I'd add to that--depending on what you do with the profit and how you handle any taxes.