Certain household electronics chew up batteries like there's no tomorrow, so perhaps it's best to get a larger pack such as this one so you're all set for a while?
From Amazon
Duracell Plus Power DUR018167 AA Batteries Pack of 8 + 4
TradeNRG
Duracell Plus Power AA Alkaline LR6 Batteries MN1500 1.5 Volt Pack of 12
Powertool World
Duracell Plus Power AAK12P / AA Alkaline Batteries x12