You can earn Reward Point for future orders. You can buy some items for free with this points.
Quantity of Reward Points depend on cost of items and type of producer.
Check quantity of your Reward Points you can in your Account Page. And buy free items you can in special category - Secret Shop (here is it).
To Apply Reward - add item in cart, and checkout it. In Checkout page you can find function - Use Reward Points. Use them.