Real property - Primarily, this consists of developed land with buildings, usually acquired by the federal government for a specific purpose, such as a military base or office building. This also includes some U.S. Forest Service properties, which usually consist of administrative sites and facilities. The General Services Administration (GSA) is the federal agency responsible for selling developed surplus property.  
Treasury Department Auctions:  The other agency very active in holding auctions is the Treasury Department, with roughly 300 sales per year. Treasury often offers in-person previews in California, Florida, New Jersey and Texas. Treasury auctions off "property forfeited as a result of violations of federal law enforced by the Department of Treasury or nonpayment of Internal Revenue Service taxes," according to its website. There are many categories of goods, including concrete items like antiques and coins but also less tangible property like stocks and patents.
The following link will take you to the sale list for the next abandoned & confiscated vehicle auction. Be advised that some of these vehicles will not be present on the day of sale, as owners/lien holders will have reclaimed the vehicles. You must be present at the sale preview to know what remaining vehicles will be offered and to view vehicle conditions.

... Back and Zender (1993) andWang and Zender (2002)illustrate the nature of these equilibria and discuss the difficulties associated with drawing sharp comparisons across the pricing rules. 1 Empirically, there are limited and conflicting results concerning the relative attractiveness of the different auction formats (compare Simon (1992) to Umlauf (1993) andTenorio (1993)). In practice, even in the relatively simple realm of government debt auctions, different countries use different types of auctions (seeBrenner, Galai, and Sade (2009)). The importance of effective governmental borrowing in the remedies to the world financial crisis serves as a reminder of the importance of developing our understanding of this important market mechanism. ...

Internet auctions typically last seven days, and operate like eBay auctions. Each listing links to the auction house website where bids can be placed. From that site, bidders are asked to register in order to bid on a vehicle. Live auctions are public auctions held at a specific date and location and are usually published in newspapers in addition to the online listing at GovSales.
In this article, we will talk about seized goods and what they are. The seizure of goods occurs when a customs officer finds merchandise or goods that are not allowed to be imported. Items that have not been declared may also be seized if the customs officer sees fit to do so. An example of an item that is prohibited, and therefore fit to be seized, is a weapon such as a knife or a firearm.
A listing of vehicles up for auction will be posted on this website as soon as it becomes available. Flyers containing a vehicle listing for this auction will be available at the Impound Section as soon as we can produce them. Some vehicles may not be listed on the internet, only on the flyer. Please do not call the Impound Section for vehicle information.
Reserve auction is an auction where the item for sale may not be sold if the final bid is not high enough to satisfy the seller; that is, the seller reserves the right to accept or reject the highest bid.[37] In these cases a set 'reserve' price known to the auctioneer, but not necessarily to the bidders, may have been set, below which the item may not be sold.[36] If the seller announces to the bidders the reserve price, it is a public reserve price auction.[39] In contrast, if the seller does not announce the reserve price before the sale but only after the sale, it is a secret reserve price auction.[40] The reserve price may be fixed or discretionary. In the latter case, the decision to accept a bid is deferred to the auctioneer, who may accept a bid that is marginally below it. A reserve auction is safer for the seller than a no-reserve auction as they are not required to accept a low bid, but this could result in a lower final price if less interest is generated in the sale.[37]
Pay and pickup. Generally, for transactions of $5000 or less, the full payment is due by the end of the day of sale, whereas for higher sale amounts a large-sum deposit might be required. Payment policies should have been outlined at the time of registration, but contact the auction company for more information. Most vehicles will be released on the day of sale, but in some cases a background check of the buyer will be required to be sure they are not the former owner buying the car back.
Auction includes over 1,000 items from State and Federal agencies, abandoned safe deposit boxes, unredeemed pledged assets from various Financial Institutions, several business inventory liquidations, several estates and other consignors. Auction will feature collectible coins & currency, rare art, fine jewelry, luxury watches, sports memorabilia, rugs, electronics, all types of collectibles & much more! 
... 2 Krishna (2002), among others, analyzes the uniform auction in which the uniform price is the highest losing bid, the multi-unit version of a second price auction. We analyze the uniform auction with the price set to the lowest winning bid because that is what Treasuries use; it is the multi-unit version of the first-price auction. Brenner et al (2009) surveyed 48 countries, of which 24 used the discriminatory format and 9 the uniform format. tion, which in turn is higher than the low bid in the uniform auction. For both auction formats, bidders shade their bids with respect to the expected value of the good, conditional on the signal observation, for all signals but the lowest. We ch ...

Buying the confiscated goods either from the TSA or individual states is done in auctions 90% of the time. Some confiscated items are put up directly for sale though, and you can find it on the websites for direct purchase. The state surplus auctions are held regularly, and if you're planning to show up for it, it's definitely best to check if you have to register beforehand. Several states require this.

HM Customs & Excise often enter items for auction seized from smugglers, fraudsters and racketeers. Executors may enter the assets of individuals dying in testate (i.e. without leaving a will) or in debt. The official receiver handles the liquidations of companies that have failed. Bailiffs will enter goods into auctions which have been seized for various reasons such as non-payment of bills or failure to keep up payments to finance companies.
Several different federal agencies hold government auctions. The General Services Administration is the granddaddy of them all, because it sells on behalf of other departments. When a federal agency no longer needs something — say, a pickup truck — it reports the truck to GSA, which first offers it to other federal agencies and then to state and local governments or nonprofits. If nobody claims the truck, then the GSA auctions it off to the public, and you get your chance at it.