It does need a gimmick, its a pretty simple and straightforward one it comes with the DVD. If you plan on giving the card to people when you preform you may need to purchase refills.
It does require gimmick.
You cannot make your own unless you are seriously that cheap. I can think of methods but cant be bothered and am sure its payoff wouldnt be as good.
Everyone is correct. You can purchase more gimmicks. I have made my own though because initially refills weren't made available. It's really not that hard. Once you take 5 minutes for a one time set up. You can make them in a few seconds. I've also made a few "more realistic" ones.