For batteries, there's so much counterfeit on Amazon, it's even difficult to find real ones.

USB sticks are rife. I had an AV project this past week; needed 40+ media players for TVs around a convention space that needed a USB stick to hold a small MP4 file.

Ordered several sets of '5-Pack' PNY USB sticks over several days, first sets the write time was 1 minute, but the second/third orders the write times were abysmal taking 5-7 minutes.

Yep. Thanks to amazon's comingled inventory

This bit me the other day, ordered a Ubiquiti UAP-AC-HD and got the Pro model instead. Returned it and ordered off eBay for a bit over $100, figure if I'm going to deal with fakes, might as well snag a deal.