Ha thanks.. but I was thinking formatted for those sheets you can use in your regular printer.
Here in the US, online business cards are so cheap, you can get 500 for around $20, full color both sides. Label paper a few more bucks and you have the ability to get 500 people signed up to NXT for pennies each, The most expensive part is the NXT themselves, but I would appeal to the community for faucet donations.
This is what I have access to:
http://www.dymo.com/en-US/labelwriter-labelsWhere are you at? Although I suppose if there was marketing budget for this, cards could be ordered in bulk, label maker could be bought, and cards labeled and shipped to interested attendees for still less than a few pennies each. I'm in the US and can handle North America, I'm sure I could find a European partner to handle the similar job.