They look to be using SanDisk Cruzer flash drives (I know this, 'cos I use a lot of these myself). The base model (8 GB) is a USB 2.0 SanDisk Cruzer 'Fit' nano drive; the other two (16 GB & 64 GB) are SanDisk Cruzer 'Ultra' USB 3.0 'nano' models. These latter two are known to be 'dodgy' when it comes to booting, by the way..!!
I feel they could, perhaps, have done a wee bit of research and chosen better drives. The choice was probably dictated solely by price; they're known to be some of the cheapest for their physical size.
There's no getting away from the fact that this is a bit 'naughty'. However, you've got to bear in mind that for the average PC user, who's probably never heard of Linux (or has even the faintest idea of just what you can do with it), this isn't really that bad a deal to 'rescue' an old piece of hardware. Yes, it's been done in exactly the same way that most of us are capable of, with one important difference; somebody else has done all the 'techie' stuff, and the end-user merely has to plug it in and use it.
For many non-'tech minded' people, that probably sounds like a good deal! Here's the purchase price of the 'base', 8 GB model on eBay for comparison:-
http://www.ebay.com/itm/SanDisk-8GB-USB-SD-CZ33-Cruzer-Fit-8G-USB-2-0-Flash-Drive-SDCZ33-008G-Retail-/142089997324?hash=item2115394c0c:g:5XMAAOSwdzVXtgsU
Many people would probably quite happily pay $20 for somebody else to do all the other stuff for them, over and above the initial purchase price of the drive. And let's face it; they wouldn't be the first folks to make money out of Linux. Even open-source needs to be funded somehow.....
Mike. 
Edited by Mike_Walsh, 10 November 2016 - 07:36 AM.