I would not want to pay 19.50 US dollars for a tin can, and have to go to the trouble of making it.
ops:
you should consider buying one of these? for 14 US dollars which is about 7.20 pounds sterling.
Take a look for yourself ? and I'm as happy as Larry with mine :P
My Power Backup came, in just over a week from Hong Kong.
Good price for around £7.20 from
http://www.dealextreme.com/details.dx/sku.3060 and works very well indeed.
So if some of you guys want extra battery power on the move.
Then I would recommend buying one of these, just a good as the Power Monkey, but a lot less in cost. The power monkey sells in the UK for around £29.00, and around £26.00 on E Bay.
Edit
Forgot to mention that I paid by Pay Pal which made it easy