Where do I buy booster items?

To enhance game play, players can purchase booster items with the rubies and coins they purchased or earned in the game. While there may be special packages that include booster items, most of the booster items will not be found in the ruby shop. Instead, players can purchase booster items before the start of each level. If you do not have the booster item, tap on the item icon and players can then purchase them with rubies or coins, depending on the booster item.