You can choose to use your coupons after placing an order. On the place order page, click on the link "Use Coupon" right above the total order price. A box with your available coupons will appear. You can select the one that you want to use and click "OK".

You can also choose to use your coupon by clicking the "View Details" button next to any order that hasn't been paid for yet. After clicking "View Details", you'll be led to a page with a "Use Coupon" link above the order price. Clicking this link will open a box with your available coupons. Simply select one and click "OK" to use that coupon.

Note: To view all your coupons, sign in and go to My Orders. Click "Transactions" along the top horizontal navigation bar and find "My Coupons" in the left column.