From time to time, I see things in contests like these (Concurs »), in which you need to buy something, then if you are one of the 30 selected, you need to take a test, and then be available to take your prize, which is a trip. There are three steps to win the product (join the contest by buying an expensive product – not easy, give a test – not easy, go on a trip – strange, still, not easy). It’s highly demotivating, even if you do win.
The solution: create something simple. “Join the sweepstakes, and you could win”. It’s OK to ask some things from the people, but do you really need to take 30 people to a test in which 2 of them will win a product? Simplify the rules as much as possible. “Buy a product, you might win”.