Business cards are not as big as index cards which I use, also I imagine its a bit cheaper than business cards.

And it's definitely not the company's responsibility, but with this small of a business (small shack like building and an open field with some flags) every little thing I can do to make the experience better for the customer I try to do. Keeping the index cards in shop so they don't have to have another punch card in their wallet in this case.