*(We'll also run a 25% off Celebration sale of our Renderosity store from Friday 21st to Thursday 27th December.)

*How does this 25% off work? Is there an amount that I have to pay, or a code that I have to put in to recieve this feature?

Because, I tried to buy "Aerysoul's Alice" and I didn't see any 25% off my amount.
(I'm sorry but I just don't understand this offer)