Figuring out the true cost will heavily depend on the type of dig down, depth, and total square footage. 

In online forums, the danger I've experienced is the "national" effect. 

When we found this deal the community had around 45 homes in it, now we are close to 60 total homes and looking to bring that number up to around 80.

We use DealCheck to underwrite deals and QuickBooks Online for everything related to accounting and budgeting.

On the other hand if you wanted the total investment to be $200K it would most likely be a condo or townhouse. 

Begin by educating yourself through books like The House Hacking Strategy and podcasts like BiggerPockets, and join online communities for support.

Spend more than half of your total working hours in an RE business in which you materially participate.2.

Explore my personal favorites, Set For Life by Scott Trench or The Total Money Makeover by Dave Ramsey, for invaluable financial insights.3.

Say they sold the properties over 3 year period and could not sell the rentals together as a portfolio.Could they put the money from each sale into a DST then use the total to buy a expensive rental property?

I use QuickBooks Online for all of my clients.