The set retails for 9900 KRW (roughly 9 Euros) and contains 5 toothpastes (2 flavors) and a "free" make-up bag. It is sold quite widely in Korea, for sure in E-Mart and Olive Young. I don't think it's available on G-Market, but maybe somebody will put it up on eBay or another re-selling store.
Obviously, the only reason to pay almost double the price of a normal Perioe toothpaste is the packaging. I have a thing for cutified/designed daily life neccessities, and I think that 2 E are still a very reasonable price for a toothpaste.
Now I can't really comment on the toothpaste quality. I think it is on par with cheaper European brands like Colgate - I have a fresh and clean feeling after using either of the flavors and I really like the sweet minty scent. A dentist I know once said that pretty much the only toothpaste that makes a difference is Elmex, and everything else is there just for the feeling - but I'm no expert at this.
The free bag - it's kind of quirky cute, and of course, "freebies" are always nice. If you consider the average toothpaste price though, the bag is worth 3 E.