Way too many variables to answer this question on this forum, your Realtor should be able to professionally advise you. If you are referring to tax value, just remember, the house is listed at 115K, it is not worth 140K, it is just over valued on the amount it is taxed. You are just trying to reasonably ascertain how much less the real value is below 115K now. Trust your Realtor. If you don't have one, I would say it could be very beneficial to helping you find a real value in your home purchase.