Prescription glasses sold at the online store is normally cheaper than those available at the local store. When you buy online, you get to use the coupon code. The coupon code can give you a percentage of discounts. Some coupon codes give you incentives such as buy one get one free. To apply the coupon code to the order amount, you can enter it during the checkout process. After you have applied the coupon code, you will notice some money have been deducted from the total order. After that, you can pay for your order by using credit cards or Paypal.