I thought of this question when I wanted to get a converter box after having already purchased a converter box.

I got the coupon in the mail, but already had the converter box. I found out that you cannot use a coupon for something that has already been purchased. You must present the coupon at the time of the sale in order to receive the discount.

You have plenty of time however to get the coupon in the mail and then get a converter box. You also have enough time to get a new TV that’s digital- just don't wait much longer!