Dear you: if you're wondering what should you offer me, please consider this: after all is way cheap and a genious idea.
The pictures say it all - these are rechargable power cells, like those I use for lot's of things, but... charged via USB. Sweet! Oh, and for those thinking this is weird, since you thought I'm not a gadget kind of guy... I'm not, but this rocks!
If you're wondering, the manufacturers claim that it takes about 5 hours to fully charge a battery, but they are working on significantly reducing this time. There is already a version of this battery for cell phones, which has a USB jack attached to it via wire, but the whole wire thing isn't as sexy as this cells. Launched just last week, the site has had over 100,000 visitors already. The battery is going to be available first in UK, then later in US. It will be sold direct online and via major chains.