Today the nPower PEG energy harvester goes on sale for about $150. The nPower PEG is about 9 inches long, made of titanium, and weighs about 9 ounces. You simply carry the PEG in your pocket, backpack, glove box, etc, and it harvests and stores energy from your movement.
This personal energy generator is very similar to the battery-less Farady flashlights in that you move it back and forth and it generates its own energy. The nPower PEG will charge most devices past 50 percent with only an hour of walking. The energy is stored internally with a lithium polymer battery and outputs that energy to your gadgets via a USB 2.0 iGo tip system.