Go to the COUNTY sheriff office website in the area you are considering, and usually they have the homes for sale on their sites. Make sure to read the "Rules" of the auction. You typically need a cashiers check for an initial down payment, then either cash or a loan within a specific time from to close the purchase.
Be advised that many of these homes cannot be seen first, and are often times in bad physical shape.
You can also check out REO (bank owned homes) by going to the HUD website and searching area by zip code.