word of caution... if you going this route (lot of houses small cash flow) you're going to want to have outside cash flow and healthy reserves. 

Stay home stay safe and stay healthy! 

The banks and investors always factor around 5 % for vacancy, so even if you are 100% occupied you will still be viewed as having spme vacancyI think 5% is a reasonable figure for a healthy market.  

My research led me to Tula, Oklahoma with healthy major industries and development.I'm looking for single-family homes between $50,000 - $100,000 with three bedrooms and at least one and a half bathrooms.

By far the best measure of "health" is using %, because end of day were talking returns, and what matters in returns is what one is getting vs all the alternatives. 

The student rental market appears healthy but I'm not sure I want to play that game.

Let's also presume the property is in a healthy market and decent location and the wholesaler wanted to sell it to me for $100K...

So over the last 20 plus years, my wife and I are proud to have very modern and healthy units.

I'm no expert at this point, but it seems healthy to ask the hard questions. 

Yes, they're very high in TX, but as long as your property is rented, what really matters is the differential between the rent ratio (which is healthy in TX major markets) and the tax rate, plus the relative rate of insurance, maint,, and other expenses.If I was moving to TX w/RE investment and a better quality of life as key considerations, I'd give San Antonio and some of the nicer surrounding areas (Boerne, Helotes, Alamo Heights, New Braunfels, etc.) a hard look.