@Jim Sun I'm sorry to hear about your losses.

You start by determining your total potential annual rental income assuming 100% occupancy and no loss.  

There are a few other major items but if I listed those someone might steal my idea, and I wouldn't want that.  

@Emilio BasaFor a conventional loan you're income is going to qualify of your Schedule E.So you could be cash flowing but depending on how you do your taxes you could be showing a loss.  

I'm not entirely ignorant of Real Estate, I just need one break to prove this fact.I want to have a home locked in before I arrive with all of my household items and no house!

If your offer isn't enough to cover what  they owe on it, personally I would pass, because they would be taking a loss and I'm not sure  how they would go about paying off the remaining balance to their lender.

I’ve saved well (nothing to spend money on here), but I don’t have a car, clothes (other than what’s in my backpack), or any items in storage.

The cost per sq ft is not accurate enough to kill the deal.It is used, as you are as a starting point for consideration.I suggest getting some hard numbers quoted on the big ticket items ie, HVAC, plumbing , and electrical and the rest is relatively cheap.Pricing per square foot works better with new construction, anything can happen in a rehab.

It took us years of researching, studying, taking losses, learning tactics and building relationships with neighbors & police in certain areas.

As soon as you close get an insurance policy to protect you in case of a loss.