The PCMCIA card is what holds the software that the Tech 2 runs on and is the one in the same GM English Card you referenced. I wanted an extra as without a working card, the Tech 2 unit is a paper weight. You won't need a separate card for each vehicle unless they are different brands that require different software (GM, Holden, Isuzu, Opel, Saab, or Suzuki). I use the same GM card for my Cadillac Escalade, GMC Envoy XL, and Pontiac Bonneville SLE. So, most likely, you would only need the GM card. Getting the extra is up to you and your ability to be patient when you have a car on the fritz and have to wait for a new card from some source if something happens to yours. If coming from China, it takes a bit of time. Maybe you can find one local, but I wasn't taking the chance for $18.
They give you the TIS2000 software, but it isn't usable. Take a look at the other board and get your software from there. The explanation is in those other threads.
The usb that the ad is referring to is the dongle to make TIS2000 work (Think of it as the key needed to start your car). The unit does not come with the dongle. As I said above, take a look at the other board and threads to get the Tech 2 to work.