I've been selling usb drives of our CD's, (as well as the CD's) for the past 4 years. To start with,I had them duplicated professionally & they printed our logo on the drive as well.They cost about $5.00 each & contained 10 CD's.
They have been selling steadily at gigs. I have since started duplicating them myself & buying 2 GB drives from Amazon. I had a CD sized sleeve printed & bought polythene bags with a zip closure, & put the drives in the bag, secured to the printed matter with blue tack.
So .... it looks professional.
All late model vehicles have a USB connector, but few if any have a CD player any longer, so that is a also a good sales pitch.