Here is a collection of 4 Sonic stickers from Prima Juice. Prima makes 25% fruit juice boxes and pops in Australia. The stickers use a rather unique style, which appeared around when Sonic Xtreme (the game that was never released) was getting a lot of buzz. You'll recognize the 'karate' one from other items. It is interesting to see that it was a part of a series, including rollerblading, surfing, and mountain climbing (all things likely considere 'xtreme' activities) The art has only colored lines on black, apart from Sonic's eyes.
These stickers were freebies with their juice products, but they're still collectible!