EB games. A great place to go search for Yugioh cards is, oddly, Walmart. The packages are sealed, so you don't have to worry about people trying to weigh or use other methods to find the super rare cards. They are readily available and almost always have the newest releases within a week of their launch. If you can't wait, there's always ebay, which usually offers relatively cheap cards, or specific cards you're searching to add to your collection.