On the other, they take 75% of the $2500 rent = $1875 and subtract the $2000 PITI for a $125 a month negative net rental income.

How will I ever find one that has enough cashflow after I subtract 50% for expenses and service the mortgage is what remains unknown to me.

After deducting 50% for expense ratios, then subtracting your debt service, you do have $210 per door.

If the comp is bigger, take the difference, multiple by this adjustment factor and subtract that adjustment from the comp's selling price.

I was going more conservative and using $1135 because I am targeting students at a nearby seminary/college and their 3 bed 2 bath on campus is $1135. ....Estimated cash flow $337.So, it looks like you took the rental income, subtracted your mortgage payment and you believe the result is your cash flow.That would be true if you didn't have other expenses, including:- Taxes- Insurance- Maintenance- Vacancy- Rent Loss Due to Non-Payment- Turnover Costs- Capital Costs- Property Management- Legal Expenses- Accounting Expenses- Etc...These things can (and likely will) eat up that $337/month pretty quickly.

Maybe subtract your estimates and try that price.The only thing I would worry about is that when you go under 100k, it's a real mental block for people.

Or do you continue to subtract from that and make a lower offer with some room to negotiate?

If it is good condition I will take 1/2 the month, 1/3 of the month whatever they give me and subtract the rest from the deposit.

Using this route, there is still risk they could get sued and a judgment added, mechanics lien, etc. to the property (they still have title remember) but my contract says if that happens it is subtracted from what they get.

First you must find out what the house needs to rehab it and subtract that from the cost.