If you sign up for one or more of the DC Shoes, Quiksilver or Roxy email newsletters and provide some personal information they'll send you some "free" stickers. They're all part of the Boardriders group.
You can sign up for all newsletters on one of the group sites. If you want to use the other brand specific sign up pages, here they are:
PLEASE NOTE: due to overwhelming demand there may be a delay in receiving your free stickers. We appreciate your patience and will get your stickers headed your way as soon as we can!
Once it gets OzBargained the delays are likely to get worse.