The property is worth exactly what it is with zero STR rental income.

--I would agree that this market has opportunities for seller finance as a record number of properties in the US are paid off. 

The other contributing factor was the poor property management and sponsor asset management of the properties.

Once they have seen the property and are interested, the prequalification and background checks will do the rest of the work in weeding out undesirable tenants for you. 

By purchasing a multi-unit property, living in one unit, and renting out the others, you can cover your mortgage payments and start building equity while gaining rental income.

To get to the next property, or any property.... you need cash.

You look for comparable sales for other distressed properties that are similar and nearby and also counter that with finished version comps so you can see what your perceived spread could be.

As you progress your bookkeeping business, you'll likely want to learn how to export statements from a variety of property management platforms, as investor books are housed in bank accounts, spreadsheets, and a variety of property management and accounting software!

Wildly enough, my first property was cashflow positive when fully tenanted.

At that point in time the market was still hot for properties at my price point in my buy box.