If the seller takes a mortgage from the buyer, the seller calculates the gain as if he/she receives all the money when the sale takes place, then the seller picks up a percentage of the total gain, each year equal to the cash received each year, divided by the total sales price.  

@Jacob Murphy totally agree.  

I am looking for an online marketing strategy or a professional who can help us manage our online presence. 

I am totally new to investing.

Your license is generally a 75 hour course (can be done on-line) and a $50 test.

That being said I've done research and came across many different online and in person courses that are offered and was wondering what agency you went through and if you would recommend the same or a different agency?

I am biased since I work for a payment service that reports payments, however your landlord would be better offer looking into a payment service so they can collect rent online and have the reporting option for you.  

All the online sites are so misleading, since they pull their comps from recent sales but never ever consider the features and amenities of any specific property.

Total rent of $2,720, passing 1%.

I would suggest doing it as a flat fee listing and not offering the selling agent anything, just use it as another place online for tenant/buyers to find you.