Depending on the agency, the government may use revenue from auctioned items to support crime-prevention programs, pay restitution to crime victims or purchase new equipment the department needs. "By providing agencies with the ability to dispose of excess assets, GSA benefits taxpayers by eliminating the need to maintain and store the unneeded property while also raising more than $300 million in revenue in just the last two years," a GSA spokesperson said.
Due to the various governmental units that supply the vehicles for auction, there's no single reason for vehicles being brought to auction. Some of the vehicles are confiscated due to the former owner's involvement in drug dealing, smuggling, or fraud, while other vehicles were simply just abandoned. On exception, separate auctions will sometimes be held for very large seizures.
Vickrey auction, also known as a sealed-bid second-price auction.[24] This is identical to the sealed first-price auction except that the winning bidder pays the second-highest bid rather than his or her own.[25] Vickrey auctions are extremely important in auction theory, and commonly used in automated contexts such as real-time bidding for online advertising, but rarely in non-automated contexts.[2]

I wasn't aware that the TSA sold all of the stuff it confiscated! That's cheap goods right there! My mom works for a cruise line, and they don't confiscate stuff, but people do tend to forget all kinds of things they bring on the ship, so every once in a while the company has a big flea market available to employees. I find it funny when my mom comes home with watches and bracelets she wouldn't have otherwise bought.