How to apply a coupon code
When purchasing a new server, you can apply a coupon code to get a discount.
To apply one, first select the server plan you want to purchase, then scroll down to the Payment Methods section.
Just type in the code and click "Apply." This will validate the code and apply the discount to your order. Then just choose your payment method and complete the payment like usual.

Note
Not all coupon codes are the same. The discount amount, how many times a code can be used, and which plans a code can be applied to can all vary from code to code.