(STANDARD RULES EDIT v1.2- change made May, 2015: The description below will differ from the First Edition v1.0 rulebook)
When a player is supposed to draw a card and there are no cards in their personal deck, that player will flip over cards from the Shop Deck (make sure it is shuffled) until there is five face up cards in a row: this is called the SHOP. There may already be some cards in the shop, in that case just fill the open slots. The player must now select their card from the shop and add it to their hand. Then that player will shuffle their scrap heap (discard pile) and put it face down as their new draw deck.
Note: The Shop will only have all 5 cards for a moment, becasue the player that opens the shop is required to take one card from the shop as their draw (either for end of turn/ Shop is Open- ACTION / or some other effect).
Additional Note: If a player would draw multiple cards (which is common with Commabackk, Dead Limb Disco or Maxine Trinidad- Crew) and the player either has zero cards in their deck (or runs out of cards in the middle of drawing cards) then the shop would open and the player would need to select the first card after the shop is open, but may choose to draw the remaining cards from their newly shuffled deck or the shop (or some of both).