Estimating home value

[Kevin K.]

I was wondering what tips or ideas or tools even that members use to judge how much you could potentially get back on a flip.  

I'm looking at a house right now that's foreclosed for 59,9. Pretty big. 1100 sq ft. I would judge the return on it by prices of homes in the area of simliar square footage ,however they seem to be anywhere from 80-90k all the way to 250k. 

I can't really employ any "70%" rules because I'm not sure if 59,9 is a good price or not.  The home's been on the market here for 4 months now.