You might also want to keep an eye out for certain cities that have planned large improvements such as new schools and stadiums as they will spike up the tax rate in a higher percentage than typical.

@Shasky Charles Welcome and glad you're taking the real estate path to buidling financial freedomSome critical books I'd say are as follows:1. 

I think HELOC is tax deductible for up to $100k on primary residence’s home improvement.

For instance, what if the tenants see a big issue that you cannot immediately service and elect to pay rent over to the court causing you to experience financial strain or even default on your debt obligation?

It depends on your financial circumstances.

Also note that you have to improve the property, land, etc. so if you purchase a home or business for say $10,000 you have to also put a minimum of 10K into it for improvement.

Whatever you offer is cash in his pocket vs losing it to an inevitable tax lien sale = no cash & eventually no where to live.Most of these 'people' are oblivious to any knowledge of financial security so I'd find out what he would take to just walk away flush with cash.

I would just caution about putting up to much Due Diligence money up front.. and be realistic about your financial capacity.

When a landlord makes a decision to buy new they entirely change the financial obligations of the tenant.

For example:  The sales price is $120,000 the rehab is $30K and the after improved value is $210,000.