These always sell out fast, so I'll cut right to the chase: Buy.com has the Black & Decker Pocket Power on sale for $10 shipped -- no rebates required.
This portable, rechargeable battery pack promises up to four hours of extra power for your mobile electronics: cell phones, iPods, digital cameras, etc. Just plug in your regular USB or AC charger and you've got juice. (On the plus side, that means no "tips" to manage, as with other portable chargers. However, it also means you have to bring along your power/USB cables.)
For 10 bucks and not a rebate in sight, this is a hard deal to beat. Definitely a worthwhile buy for folks who frequently take long trips.