Cheaters generally pick through boxes and sort of move things around, either hiding the real choice thing or moving a choice thing into a box of other choice things. It's totally wrong and the auction people would throw them out if they were caught. But it happens and it ain't pretty. So for this old gal, personally, I really avoid that real auction scene, it brings me down. But it is fun to burn up a rainy Saturday if you can afford the time.
Online auctions are pretty great.
Ebay, Amazon's zshops, Yahoo's and then some. You can save a ton of time by using their search features. You can find stuff much faster and you don't have to wait for your lot to come up like in a real auction. But you gotta know your limits which means you gotta know how much the thing is really worth. Get some books on the subject.