REI offers the Goal Zero Nomad 7M Solar Panel for $59.99 with free shipping. (B&H Photo Video charges the same.) That's the lowest price we could find by $11. It features eight to nine volts of power and USB- and 12V-compatible charging ports.

Update: It's now out of stock at REI; however, B&H Photo Video still offers it for $59.99 with free shipping.