Are car auctions really good to buy from?

i live in orange county california and want to buy a mini cooper…a friend told me of these auctions and how great they are and how you can get cars for much cheaper than normal…are there a lot of auctions down here and are they safe to buy from? my friends relative will be going with me since he does this stuff all of the time.

also, are there any sites I can look on that will have cars available and up for auction? thanks!