Selling Flash Drive at Cyber Cafe

When I was work at hubby's Cyber Cafe, a few times I came across customers asking whether we sell flash drive. We do sell Floppy Disk, CD-R and DVD-R but not flash drive coz it is kind of costly. But then, not many of us use floppy disk anymore. New computers does not come with floppy disk drive too. I wonder where can we buy cheaper flash drive like the ones selling in Tesco. If can get cheap Custom flash drive even better. :D