The Miracle Shooter is a new multiplayer battle feature introduced in Pokémon Black and White. During a multiplayer battle, if both players have the Miracle Shooter enabled, they will be able to purchase the use of certain items using points that are accumulated each turn. Unlike in-game battles, the player cannot use items from his or her bag; instead, there is a select set of items available to the player, including several items exclusive to the Miracle Shooter. Each item has a certain point value which must be paid in order to use the item.
Here are the items you can get and their cost
Item/Cost
Item Call/1
Potion/2
Skill Call/3
X Attack/ 3
X Defend/3
X Special/3
X Sp. Def/3
X Speed/3
X Accuracy/3
Dire Hit/3
Guard Spec./3
Super Potion/4
Antidote/4
Parlyz Heal/4
Awakening/4
Burn Heal/4
Ice Heal/4
Item Drop/5
X Attack 2/5
X Defend 2 /5
X Special 2 /5
X Sp. Def 2/5
X Speed 2/5
X Accuracy 2/5
Dire Hit 2/5
Full Heal/6
X Attack 3/7
X Defend 3 /7
X Special 3/7
X Sp. Def 3/7
X Speed 3/7
X Accuracy 3/7
Dire Hit 3/7
Hyper Potion/8
Flat Call/9
Max Potion/10
Revive/11
Ether/12
X Attack 6 /12
X Defend 6/12
X Special 6 /12
X Sp. Def 6/12
X Speed 6/12
X Accuracy 6/12
Full Restore/13
Max Revive /14
http://bulbapedia.bulbagarden.net/wiki/Miracle_Shooter