Are you only accepting BTC for these cards or can people buy them with USD?
Also how does one make change?
This will initially launch btc payment only. I will in the future be accepting other forms of payment as well as offering redemption of still sealed cards for currency I will likely accept bitbills for redemption as well.
If all goes well I'll accept other payments before the first series is sold out. If not I'll strive to have other payments online for the next series.
As far as change goes, if the card is to remain a sealed trade unit than change would have to be in smaller denomination cards, or alternative currency. The change solution will come with centralized processing which others are working on.