Buy the Generic Battery.
When it comes to the standard alkaline battery there is no difference in longevity between name brand and generic batteries. These test have been run both scientifically and unscientifically. (Sounds like a great kids science fair project idea) Check them out at: MoneyWatch.com, Xfinity Finance Report, batterytruth.info, Consumer Reports (must be member).
According to the Money Watch report, there is of course one exception to this advise. The Energizer Advanced Lithium battery lasts the longest by quite a bit but the price difference still may make you pause. About $1.42 each for the Energizer Lithium vs. $.42 for the Raovac Alkaline.