I paid $15,800 for my VZ SV6 with 135,000kms on the Clock. Prestine condition inside and out. And I just picked up my new VZ Acclaim for $12,400 with 116,000km on the clock. Same condition. Both with good log book history and a very helpful dealer.
My advice - have an RACQ Mastercheck done before purchase. Yeah it may cost you $180, but they give you a great idea if there are any issues with the car, and I was forthcoming with the dealer and showed the reports, which they were more than happy to fix what ever was found without question before purchase. They also appreciate the reports to know what sort of condition the cars are that they are buying too.
When I was looking around, I checked out an Auction centre, which had two VZ's (An Equipe and an Executive), both under $10,000. Bucket load of km's on both of them, and one had a Airbag fault warning on startup, which the salesman couldn't care less about. This auction centre sells the car on behalf of the owner, so there is no option to screw them down on the price, as the auction centre has already done that to the seller. They will not organise a RACQ Inspection, and you pretty much buy the car as is. The Warranty is pretty ordinary as well, as mine both had 5,000km or 3 month Warranty if there were any issues located within that time.
Police auctions - As I have said in a previous post, I have pulled enough people out of the back of police vehicles that have been covered in blood, vomit and any other bodily fluids you can think of, and no matter how hard you try to clean it, its always going to be there. D Cars would be my choice, for one being that they are not all white, and secondly, they wouldn't get as much of a workout compared to a generals unit. All are serviced well.
I just set a limit on which I could afford to spend, and kept checking the websites and looking through any car yards in the area keeping to these specifics.
Hope this gives you some ideas on whats out there.