While no one will ever label investing in certificates of deposits sexy, you can't blame Washington Mutual (NYSE:WM) for trying. The bank is teaming up with eBay (NASDAQ:EBAY) to auction off hundreds of six-month CDs through a new website.

Taking a page out of the Priceline (NASDAQ:PCLN) playbook, the "Bid Your Price" promotion is more of a novelty. The CDs are all $1,000 instruments. It's clear that the company is doing this to lure new customers and win a little media loving. You won't find any mention of the auction on the bank's actual home page -- and with good reason.

Banks have historically paid crappy rates on CDs. If you're a customer doing business in person at a branch office, they know that you are as good as captive. Depending on where you live, Washington Mutual is paying out either 0.95% or 1.00% on its four to eight-month CDs.

But that's not good enough in the online world. Rival banks are just a click away, so rates have to be competitive. Head out to our Savings Center and you will see MBNA (NYSE:KRB) offering Fool readers a six-month CD that is currently yielding 1.54%.

That's why the real surprise isn't that the rates on the Washington Mutual auctions are coming in a few basis points above the walk-in rates. No, that's a given, and it's why Washington Mutual probably doesn't want its existing customers to be lured into its own auctions. The real shocker is that folks are bidding those CDs down to 1.2% -- or less -- when the virtual world is considerably more rewarding.

And, yes, this is eBay doing reverse auctions here. Unlike its flagship marketplace where members bid items higher, these standalone offerings have potential clients bidding yields lower.

But that's the power of eBay, isn't it? You won't see other Web-based auctioneers like Yahoo! (NASDAQ:YHOO) or Amazon (NASDAQ:AMZN) break out of their molds the way eBay has to appease corporate clients with customized services. That's one of the many reasons why the stock was one of the earliest -- and successful -- Motley Fool Stock Advisor selections.

So, just remember to check the next time you want to buy a CD from eBay. You may find money -- not music -- inside. Then again, money might be music to most ears.

So, what do you think of eBay and Washington Mutual teaming up to auction off CDs online? Will it help -- or hurt -- Washington Mutual? What will eBay do next? All this and more -- in the eBay discussion board. Only on Fool.com.