I operate strictly as a business, I am neither a social worker or a charity.

My focus will be to stick to stable properties with value play potential in markets that strictly follow the market criteria I plan to use.

Like @Stanley Bronstein said, many communities have VERY strict rules about AirBnB's or STR.  

If you are strictly looking at investing, don't actually get your license. 

It is not a given that all such communities are strictly "affordable housing".

If you are strictly wanting to practice calculations, then, you could use sq. ft. and apply several different price metrics.  

I have a strict no evictions in the last five year policy and no previous landlords in collections policy period.

The tenants gave me the okay that they were fine with only 1 of them on the account, but I'm a bit un-easy that I may be screwing with the very strict MA rules surrounding Security Deposit Account.I ended up setting up a single account with 100% of the security deposit in it.

They just said this to my fiancé (they prefer to deal with him instead of me because I’m more strict lol!)

If the unit is in an HOA, then HOA will likely strictly forbid running a business out of a home.