Try the link at the top of the page called "Order Status/Account". Once on that page scroll down and there should be a panel called Gift Cards with a link to "View and email my gift cards" and that should be where you find all codes for existing gift credit which you can apply to things when you checkout.

it is is active you just use the code on it. To get to it select order status/account (top of page) scroll down until on the right side you see View and email my gift cards click on it and you will see all of your gift card and the amounts enter (cut and paste ) gift card code when making you purchase

When you received the Gift Card you should have gotten a code to use for purchases. If you did not, Buds Customer Service can assist you at Live Chat in the lower right corner. You can click this link for your registered Gift Cards and codes : budsgunshop.com/gift_cards.php