You can purchase USB keys in bulk for around 1.50 U$D. How is this not a viable solution? Floppy disks today seem to cost only about half that price.
http://www.amazon.com/dp/B00E3MII96/
Not exactly cheap, if you ask me. Not exactly super-expensive either, of course, but definitely not cheap. And I think the reasons the price for floppy disks doesn't seem to go down is because only certain people still use floppy disks, i.e., the need for floppy disks is nearly non-existant.
eBay, Alibaba, or contacting the wholesale division of any of the stores you get searching "bulk flash drive" on Google would be a better idea. They start around $2.50/drive retail with your logo custom printed, so you can do much better wholesale.