Let's say a developer sells condos that have a fair market value of 90 k.

So what is your exit strategy - long term hold, sell and 1031 to a larger property, or other?

I am in Cincinnati, where duplexes generally sell for less than single family homes.  

All agents are incentivized to sell it's a transactional business and because you are just starting out and in a low barrier market you will encounter many new agents who need to eat and pay for their gym membership and car that month.   

When the property sells, They get a check at closing for their principal and interest.I ask them if they want to loan their money on another property.

If the traditional model is used, hypothetically if gross commission for the whole transaction was $10,000 split evenly between listing and selling agent, each side would receive $5,000.

Of course, they also offer an unparalleled warranty on the notes they sell, so that is probably worth a premium.

Sell it in two years.

do you sell the duplex to pay off the mortgage or what do you do?

For an exchange, they want your intent to be that you hold the property for long-term business or investment use (for both the property you sell and the property you buy).