I was surprised when they told me that they have never done credit checks.

After starting repairing a house, I realized that I should have negotiated harder because the repair cost was going up and up and facing with unexpected inspection issues and other issues with a un-trustful contractor.  

To my surprise the house was on his list of homes.  

A couple of caveats; 1) As this is an older property, it would not surprise me if the expense ratio was higher 2) Carrying cost are not included 3) Unless you have done this a few times before, renovation costs tend to inflate 4) Your time / effort is also not included.

If it's as good of a deal as your numbers suggest, I would be very surprised if it sits for long. 

It seems like you offering 150k but also telling them that you would be willing to go to 180k would just mean that, surprise, we got an offer for 178k. 

I also opened a line of credit with a local bank to handle anything unexpected. 

If you are using hard money you need to budget for the points and fees as well as traditional third party closing fees.Repairs: The money it is going to take you to rehab the property plus an extra 10% of estimated repair costs to account for unexpected repairs.Holdings Costs: Here is where a lot of investors get tripped up.

If your circumstances just HAPPEN to change unexpectedly (as opposed to "unexpectedly"), then you should be OK.

Obviously, lenders like to see as much padding as possible because it means your more likely to be able to handle vacancies, a softening rental market, or any other unexpected scenarios.How are you planning on financing the deal?