Many of us have surplus 5 volt AC/DC chargers for cell phones we no longer use. Those chargers could be useful for a variety of power sources if there were a way to attach a female USB connector to the cord and do it for little or no cost. But, stores like Radio Shack do not list a female USB connector in their on-line inventory. USB cords with a female end are expensive unless you happen to have a non-working USB cord with a good female end. Improvising one's own female connector becomes an attractive option and others have done that. But, the base material for a connector needs to be quite sturdy, thin enough, and there needs to be a way to attach thin circuit traces. This Instructable is an approach I attempted. It worked with some devices, but not with others.
The photo shows the female USB connector on a car charger for a USB device.