If the Pre-for-a-Benjamin deal sounds familiar, the likely reason is that Sprint (briefly) pitched a similar deal just two weeks ago. On Sept. 8, the wireless carrier began offering a $100 service credit to Palm Pre buyers, which in essence lowered the phone's price to $100. Sprint is the Pre's exclusive U.S. carrier.

But in a bizarre turnabout, Sprint pulled the deal just hours after posting it on its web site. The company later released a statement that the offer was nixed "after further internal review," and that the deal had been "put into the system in error."

Amazon's discount looks like it's here to stay -- at least for now. When asked to comment on the Amazon offer, Sprint spokesman Mark Elliott wrote via email that the wireless carrier's sales channel partners can "set their own price for devices," but he didn't say whether Sprint would match Amazon's $100 deal.

Perhaps Sprint should. An unconfirmed report from financial news site claims to offer the Pre early next year. Sprint's lackluster Pre sales played a major role in Verizon's decision, according to The Street.

As I've written previously, I believe the Pre's a very good smartphone that has been underappreciated thus far. A lower up-front price may be the push it needs to attract new users.