Making #'s make sense

[Lee Haenschen]

I'm very new to the market here, so please go easy on me! 

I've read a lot of books and a ton of BP podcast and everyone makes this stuff sound easy.

http://www.greatercarolinas.net/index.php?action=l...

Above link is a property that I wanted to use as a example to help myself learn what numbers are important to run on that property to see what needs to be my offering price to make it a good deal.

From all my reading I understand that you can't buy anything at market price that it needs to be considerably below market price. How do you understand what market price is? Just my opinion that most put an inflated price on the homes when they are listed.

Just running some vague numbers on the property above.....with me knowing very little about what I'm doing I'm missing a ton of important numbers here.

Asking price is $139,900 for the duplex (homeowners pay their own utilities btw) 

Lets say I offer $130K and pay half of closing costs. In a perfect world I would get a mortgage interest rate between 4.5-6% with 20% down with escrow my payments would be around $777 per month + withholding around $150 per month for maintenance & $75 per month for vacancies. 

IF the rent is $550 per unit that would leave me with $98 per month total cash flow. And im sure that would get gobbled up by some other % that I didn't equate for.  I tried reverse engineering the numbers to figure out what I would have to offer to make it profitable. It seemed like around $85,000 would be the magical number. I know getting deals at far less then market value is the name of the game, but how do you go so low on an offer without the realtor saying don't bother submitting the offer, your ridiculous....get out of my office! ??