There are 3 kinds of online auctions with Dubli.com. Xpress - which is somewhat like reverse auctions common in business to business, but this is for consucmers. You spend 80 cents to view the price and every time a price is view it goes down by 25 cents. This is the one auction of the three you can really control how much you save, at least until some one else grabs it before you do.
The next is lowest unique bid. Just like it sounds you have to spend 80 cent credits to try to find the lowest unique bid. You can burn through a lot of cash BUT the savings can by quite large. It can be a good ROI if you work a stratgey and can control your self
The zero bid is the one to hit the enter key right when the price goes to zero get it. Timing is everything and some luck is needed but again the savings can be large.
You can see the auction results at Dubli Review
Again the least risk but lowest savings (but still some good savings) is the Dubli xpress auction. The highest risk but chance for best savings is the zero auction. Good Luck!