It's becoming a pleasant tradition of CS:GO tournaments with prize fund of $250,000 to release stickers of teams-participants of upcoming large event. Stickers may not only be attached to a personal weapon, but also used during the in-game competition Pick'Em Challenge.
What do you need to become an owner of a sticker with HellRaisers logo? Put some money on your Steam-wallet and then, in main menu, in section "DreamHack 2014" buy a sticker of your favourite team! Price for one sticker is 0,99$.
By purchasing stikers you not only get a decoration for your weapon, but also help teams, whose stickers you buy! Partically, money from stickers go directly to the teams, and that helps them to develop, visit more tournaments, etc.