The first thing that you have to understand about a sherrifs auction is that more than likely (probably a 99% chance) the very first bid will be from someone representing the bank or whatever asset firm may have the mortgage. This is occasionally also done by a lawyer that will have numerous parties that he is representing. Usually that first bid will be what the mortgager (bank) is owed. It could be a $20,000 pile of junk but if the mortgage that the bank was due is $50,000 that first bid is "usually" going to be $50,000. If you want to buy it at $50,001.00 they will be more than happy to let you "outbid" them. The crazy part about all of this is a year later or more, they might actually take the home that they bought for $50,000 that has sat empty the entire time and put it on the market for $20,000. This is the world of foreclosures, REO's and sheriffs sales. I can't give you any legal advice but buyer beware at a sheriffs auction. There may be more attached to that title than you know about or want. Occasionally you are also responsible for your own evictions.
Best of Luck!!