I've been to a police auction -- and I've been to a couple car auctions.
But not a Police Auction for cars.
At the police auction, there were "bins" or "piles" of stuff that peeps would bid on -- ranging mostly from jewelry and art to electronics like stereos and boom boxes. It was before computers were the biggest thing ever, so I imagine today there's piles of PC's and video game consoles -- all "as is"
The car auctions were a bit more interesting. Prior to the auction, you could start them up and look through them. I don't think they allowed a test drive -- just a start-up.
The price range for winning bids were all over the map. Some seemed way under and some seemed way over what I'd consider "fair" (disclaimer: I'm no car expert).
I remember one car in particular that was really bad.
The peeps were all in a kind of barn/warehouse and they'd drive the cars through to be bid on one by one.
The car smoked so badly from the mufler and also INSIDE the car, the guy doing the driving had to exit the car during the auction. They hurried the auction along as smoke poured out of the interior.
Interestingly, there were also boats at the "car auction".
A long time ago (10+ yrs) I knew a girl who's boyfriend bought cars at auction, cleaned them up and resold them. They were'nt well off, but I imagine a mechanic could probably make a modest living doing it.