If you wanted to add more decks, a t-shirt, a poster or an uncut sheet to your current pledge you can do so without having to create another account. Simply refer to the Add-On Guide that is provided near the bottom of the campaign page. Take the total dollar amount of the items you want to add to your pledge and add it to your current total.
For example (domestic):
If you pledged for 1 Piff Deck & 1 Piff Shirt but wanted to add one more deck:
$35 (tier) + $7 (shipping) + $14 (extra deck) = $56
By adding $14 to your current total pledge, you'll enter the new total which is $56. Once the campaign is over, you'll be able to confirm your add-on through our management account on BackerKit and in the Kickstarter Survey.