CREATING A KEYCARD WITH LIMITED NUMBER OF USES

Hi everyone, i wanted to ask how possible it was to create a Keycard using Arduino to access an Arduino controlled Vending Machine but giving the Keycard a specific number of uses after which it will no be active but can be reactivated. See it as having a credit card with $20 and after the $20 is used up, the credit card is no longer useful unless refunded

ROTEX:
Hi everyone, i wanted to ask how possible it was to create a Keycard using Arduino to access an Arduino controlled Vending Machine but giving the Keycard a specific number of uses after which it will no be active but can be reactivated. See it as having a credit card with $20 and after the $20 is used up, the credit card is no longer useful unless refunded

Cards with magnetic stripes have three magnetically encoded stripes. Each one is encoded differently. As I recall only strip #3 is the only one that can be rewritten by a public machine. Do you have equipment with that capability?

Paul