Hi Palm,
I like the idea of the contest but I would make sure that the contest will have full of designers who participate this program. I would recommend to add more benefit to the winner by giving them percentage from number of stickers sold. I am afraid that the benefit for the winner is not exciting enough. To do good design nowadays, 30,000 baht winning prize is not value enough for professional designers.
Rip Curl has been work with a few famous street art designers. The incentive from sales made them do good work for the brand. We also have power to make strong deal with them.
Let’s do big contest by giving big prizes which I believe that you will get loads of contestants.
What do you think?