So, essentially this site is just reselling Raspberry Pi's with a few pieces of software source code pre-downloaded to the SD card? I'm really not seeing the value add here.
I think you are underestimating the value a person places on the time to put these pieces together. If you are a student, $20 is a big premium to pay to order a PI, an SD card and then downlaod some software to the SD card and install it.
I have a couple raspberry PIs I have used for various applications. I decided to put together an arcade emulator as a gift to my son. I know how to make this. But if someone sold a PI arcade emulator with the card installed I would pay $60-70. With a controller, a $100.
I'm not sure why this got downvoted. They are charging 0.03BTC (which Google tells me is USD 17) for a 8GB SDHC card with software preinstalled. This seems pretty steep for something that anyone can setup in a couple of minutes easily. Heck, someone can even distribute the exact same thing in the form of an ISO image for free.