We do not currently offer iRacing gift cards but  what you can do is purchase a Mastercard, Visa, American Express or Discover prepaid card that they would use to purchase iRacing with. 

If both you and the other person is an iRacing member already, you can log into members.iracing.com and hover your mouse over Store and choose Account Recharge.

On the next page, choose Gift A Recharge to Another Member and then follow the rest of the online instructions.