There is no such thing as a pre-foreclosure. Pre-foreclosure is a marketing term which means a lien holder, (usually a lender) has initiated the foreclosure process. Since foreclosure notices are public records, there are real estate websites that advertise these properties as pre-foreclosures so they can sell buyer leads to real estate agents.
As a buyer, you are not able to buy or see pre-foreclosure homes and I would avoid inquiring about any property being advertised as such, (unless you want a desperate Realtor calling you about a home you cannot buy). Furthermore, the owner still holds title and maintains ownership rights until the sale is confirmed via the sheriff’s office. Therefore, a bank cannot sell you a property they don’t own yet. The time a foreclosure is initiated until the time the sheriff sale is confirmed usually takes 18-24 months with some lasting up to 4 years. In addition, the price shown on the websites is based on an exterior appraisal or judgment, neither of which represent the value or what the property will be listed for once title transfers.
If you are interested in foreclosures, (bank owned listings) they are on the Multiple Listing Service. Once the sale is confirmed, the banks can list, show, and sell the property to any interested party.