Ask HN: How to cheaply print cards with different qrcodes?

Hello, my startup use some cards to recognize the customers of our customers. In these cards we must have a different qrcode for each of them.

Currently it is quite expensive to print all these cards.

Do you know any place where I can do this printintg cheap? (I'm in Brasil, but depending on price I can import them)

May you help me think in another approach for this? Maybe making our customers pay for the cards, or a different tech approach.

We use qrcodes because it is easy to be recognized in tablets that we provide to our customers.