For your searching you can easily set up auto searches on www.themlsonline.com and keep track of what's available (at least on MLS in the twin cities)

I usually round up to the next closest 1000 dollar mark. put it on auto pay them let it go.so say I have a 2300.  

Here is what I would do if I were you. go check out the vacant unit, the basement to check the mechanicals, and check the roof. 

Hopefully you had him waive the right to a mechanics lien. 

If it would help, I would be happy to set up a "vacant land" search on MLS with your criteria.It gets auto-delivered by e-mail to you.

Additionally there is STNL properties that are free standing single tenant buildings such as a pharmacy, bank, dollar store, auto store, restaurant, etc.The value of those properties tends to be based on location, quality of the tenant, length of the primary lease left, and any termination clauses or where it's a NN and not absolute NNN.You won't find a brand new regional or national tenant property at a high cap rate.

Sorry, I meant to type POLYBUTYLENE but auto correct changed it.  

Avoiding Sales, I've remained in the service side as a member of the E-mail team, handling policyholder questions regaring auto, motorcycle, homeowners, and renters insurance questions.

Things that might not possibly be obvious during the standard mechanical inspections.

Be sure to start looking into your support mechanism for when things go wrong inside the unit.