Websites that facilitate custom USB flash drive purchases include CustomUSB.com and USBMemoryDirect.com. These website often sell a variety of preset base drives that can be customized with more specific details.
Custom USB devices are typically more expensive than standard flash drives, and they are most often sold in large lots rather than individual units. Customized flash drives are most often used by businesses that want to leave their brand on the drives as promotional materials and need to pass out a large quantity of them.
Anyone who wants to customize fewer than 10 is likely to have a difficult time finding a customizing service and may need to alter an existing flash drive personally. This task can be as simple as painting over an existing detail or as elaborate as disassembling the plastic shell encasing the electronics of the USB stick and transplanting it into a separate case of the user's design. The latter option is not that difficult, as most USB drives have their casing snapped around them, and the connected parts of the casing can be snapped away from each other. From there, the device can be hot glued into whatever casing the user wishes. As long as the plug at the end of the drive is still fully exposed and can be pushed all the way into a USB port, the glue does no harm to the electronics.