If the credit screening costs $25, then you earn nothing.I believe there are exceptions for a higher fee, but you have to stick to the actual cost of the screening.I would talk to an attorney before charging more than $25 per applicant.

what if appreciation is low for the next 2-5 years?

Way better returns on the cost seg than you'd ever cash flow from an LTR. 

Modular, on the other hand, which I also deal with, you can do a mod and put it in the city limits but would cost as much or more as a stick built, more if you go with a two story.You're much better off going with an existing duplex

Luckily, we were living in the house when properties were appreciating like crazy and interest rates were low. 

You will really need to look hard in order to find deals that make sense and you really need to take you cost of capital into account when doing your analysis.

It appraised for $201,000 and I put $103,000 in my pocket after closing costs and previous mortgage payoff. 

Far more costly to transfer property at a later point than simply purchase in an LLC on day one.

It may cost you more in the long run.Good Investing... 

The newest outdoor is still advertising 1st month free as they haven't filled up, and I spoke with the climate controlled owner/builder yesterday (he's a pretty big REI in the area), and he made it sound like he hadn't leased a single climate controlled unit since they opened a few weeks ago.I recently purchased a 140x45 warehouse with low ceilings and had debated doing self storage, but my market seems very saturated.