I think it's a scam.
I'm ashamed to admit I did this and no, I didn't win. It's like gambling, the odds are always against you and there are a lot of unknowns. After 3 hours and $100, I learned a lot. First, I strongly believe there are people who work for the auction company who "up" the bids.
Then, I had a very sketchy experience. I was bidding on a $200 GC to Lowes. Right next to my bid was a $15 Home Depot card + 50 Quibids. I learned to wait until LITERALLY the LAST SECOND to put in my bid. When the current bid was $76, I had no problem getting my last second bid to count. However, when no one had bid on the $15 Home Depot GC next to me, I entered a bid at the last second. BIG SHOCK that I submitted my bid too late to count and that auction was closed w/o a winner.
If you scan the site as a lurker, it'll look like "oh wow, that Ipad only has 5 seconds left to bid on and the high bid is $50!!! OMG, I have to do this!!" The reality is, whenever somone enters a bid, even if you're down to the very last second, 15 seconds are added to the countdown. I spent over 1.5 hours bidding on something that went down to 1 second over an hour ago. KWIM?
After I left the bidding, I received an email from Quibids offering to sell me the Lowe's GC for the balance of it's worth, taking into account what I already bid. For example, I bid $100 for a $200 GC. They offered to sell me the GC for $100.
The Quibids site itself even states bidding can take a lot of time and money. They fall just short of warning you that's it's a gambling site with the odds stacked against you. Google "penny auctions"...you'll find some very interesting facts.
I would never do this again.