I can understand that when looking at foreclosure auction prices, most of the properties look like a bargain. You have to understand where the auction price came from, before getting too excited about it.
Let's first understand how the property happened to be in foreclosure. A common reason is that current owners did not pay their mortgage or tax bills on-time, causing bank or municipal/state/federal government to place a lien against the property, in other words, the mortgage lender or government wants to get payment on the current owner's obligations by any means, even if they have to go through the foreclosure expense and auction the house to recover the owed amount or gain possession of the house to sell it latest via real estate agency (REO properties).
If the current property owner had a single lender, then the amount you see at the foreclosure auction might be the only debt against this property (key word is might). In the case where the current owner had, say, a home equity loan in addition to home mortgage(s), there may be two or more liens against the property from different mortgage lenders. Whichever lender files "notice of default" first and puts a lien against the property gets to foreclose on the property first. The payout from foreclosure action to lenders or government always happens in order of court filing. The only way for you, as an investor, to find out what liens, mortgages, and debts exist against the property is to order a Title search.
Foreclosure auctions (sometimes called sheriff's sale) are typically held in the municipal (county) courts. The County does not offer you any protection against additional liens on the property, nor do they guarantee you a clean title. Lenders or government agencies are always represented by top-notch real estate lawyers, which do not care about your interests and are only interested in selling the property at the auction.
Please, allow us to be your Foreclosure Title Search Service Company. We have vast experience in foreclosure title searches and pay a great deal of care in performing the search as accurately as possible. We recommend a Full Title Search service to be sure that there are no liens carrying over from the previous owner and current owner. For REO properties, you will have to order our Full Title Search service, since the current owner is the lender, while the liens are carrying over to the property from a previous owner(s).