And can anyone send me a solid formula for evaluating properties to know if i have landed a good deal?

As long as both of you are happy with it, that's the formula for success. 

There is no formula for that because part of the calculation is an intangible, the value you put on your own home. 

For simple 1-4 unit properties my above formula is what most lenders would use. 

@Ryan Davis what @Chase Gochnauer is saying is that every municipality calculates taxes different and uses different formulas to asses a property's taxable value.

I am not comfortable with allowing that as her income may not satisfy my formula for affordability on her end.

Just as important as it is to stay hydrated! 

If the strategy is to buy, add the unit, then sell shortly afterwards, I'd find the new value using the formula VALUE=NOI/CAP.  

so I just finished at 3 day class with flipping formula and the guys who did the class had the nerve to ask us 4 an extra $40,000 to take an advanced class what do you guys think about that and there were a few suckers that paid it now the advanced class was they were able to get mentors or the mentors would help them find properties and walk them hand-in-hand through the cell or the wholesale or the rehab of the property that they decided to build on or whatever then they also were able to go to an investor Summit and Las Vegas and you know a few other things that you know came with the $40,000 now mind you I was highly upset because I had already given $2,000 for the 3 day class and they really didn't give us anything the only reason why I did it is because I can get my $2,000 back if I can make a purchase and sell in 90 days I'll get it back or if I don't make a purchase or a cell in 6 months I can get it back so tell me what you guys think

@Leyla Simsek a shortcut to @Chris Vail 's reverse engineer offer is to use the MAO (maximum allowable offer) formula.