They have these often. First time it was instant delivery via code, and you could use the card to buy another card. That diddn't last long, cause you ended up with unlimtied cards with $5 left
You typically cannot immediately "roll" the card you buy into another card (to get a free $5). eBay is on to that hustle, and you generally have to wait until the next time the cards pop up for sale to "roll" them.