Auctions are usually cheaper than car yards (and sometimes private) but there is no warranty and you usually can't test drive the cars. Private buying can be a hassle, drive all over town looking at different vehicles, finally decide on the one you want, then get a REVS check (highly reccomended but not mandatory). If you are getting finance banks usually aren't as keen to lend you money for a private sale. Car yards can be a hassle too, high pressure w@nker salesman that don't know Jack about cars and only want to flog you some overpriced dog, usually pay several thousand more $$ but you do get guaranteed title. You usually get the choice of a few cars to pick from. Car yards can organise finance and insurance (at a price...) on the spot. Used cars usually have warranty, but it can be a problem sometimes actually trying to claim on this (been there, done that). They will usually find every excuse in the book why it's not warranty and then if you finally manage somehow to convince them that it is they mostly just do a quick slap up job to fix the problem.
You know, somebody actually complimented me on my driving today. They left a little note on the windscreen. It said, 'Parking Fine.'So that was nice.