Yeah I've seen people waste so much money on bids they just burn on certain items its crazy. Kinda like the people who split Kings on the blackjack table.
So far I've gotten 2 copies of CoD Black Ops, 2 doz golf balls for next year, a pair of Spy sunglasses for my wife, and a 25 bid voucher for around $110 including my bid purchases and saved a grand retail value of over 200
The way I do it is, I find an item I'm willing to pay retail value for and buy just enough bids to cover the purchase cost using the buy it now feature and then bid til I win or have to buy it now. I use my remaining bids to grab other items that I know I can get for only a few bids