Not a flashaholic tip, but a tip nonetheless: if you buy USB thumb drives, memory cards or flash-based mp3 players, always make sure to carry a notebook computer with the appropriate checking and formatting utilities with you (standard windows format probably won't do).
There have been many cases of flash memory devices with hacked firmwares reporting far more capacity than they actually have. I fell victim to one such scam too (although it was an eBay seller who eventually refunded me), and let me tell you, it's not pleasant.