In the Bigger Pockets free book, "Real Estate Rewind", as one of the 11 co-authors I wrote about one such Tax Sale purchase and made money but not enough money to warrant the risk involved.

Quote from @Brendan Doherty': I’ve read in books of people getting past having to live in the property they own so they can rent all units year one of ownership(living on the property with an rv).

I share an example in my book where five people wanted to rent a 5bed/3bath house (one boyfriend/girlfriend, and three other friends).

@Chris Kay - Bigger Pockets has an older book now called "Estimating Rehab Costs" that was published prior the pandemic.

Btw, I learned about this from a book about the career of Harold Helmsley (pre Leona!)

BiggerPockets has great books and podcasts for beginners.

However, leaving them where they are I feel like I'm missing out on bookings. 

Appraisals, Lenders and Rates : Beyond the transactions that were literally in process (sales, listings, leases, seller carries) are properties that remain amongst vacant lots.

Interesting that this seems to cover all property zoned residential, with no apparent carve out for a transaction of residential property between two investors.  

That book gives a lot of great information on underwriting.