This is assuming both apartments generate equal cashflows and are equally priced.

If they are real nice, I'll give them a bottle of mead from the bees. 

He bought a few properties for cash to generate monthly income and now he can qualify for loans.

Typically over in our area (Lakeland) the responsibility is with the tenant that generated the bill, not the landlord - or the previous landlord if it was landlord paid.  

A photo site should have a way to generate the proper posting string for you.

I invest on the side to generate additional passive income, but I do not want it to become or replace my full time job.

In principle, I love the idea and of generating some extra passive income assuming it's worth your time. 

@Nathan Gesner new subfloor, Killz and an ozone generator.

You "pay rent" so that the property is generating cash flow and split that cash flow according to your agreement.

Auction sites are another source that can get you a property that generates a good return (our last one returned $50K and again, when you are selling properties for under $150K, we welcome those returns but in other areas, one does not get out of bed for less than double that).