Once you've added your product to the cart you should be redirected to the shopping cart page.
Here you should see a box on the left, just underneath the products you have in your cart.
Enter your coupon code here (indicated in the image with a red arrow).
NOTE: If you click paypal on the product page you will not get the chance to add your coupon. If you click 'add to cart' you will still get the option to pay by PayPal.

We do not ask for any proof of Concessions, and hope to be able to offer these to anyone who needs them. With this in mind please be honest.