My mistake, they're not AA's. They're the much more deadly C's or D's. Can't tell for sure.
How about watch batteries? Puny compared to C's and D's, but still deadly at close range ;).
About 15 years ago, around Christmas time, I received an extra large edition of the New Yorker. Bound in the middle was a thick insert: an ad for some Scandinavian vodka. The theme was the Twelve Days of Christmas. Each of the days was represented by a window in which the light flashed on and off.
Being curious, I ripped the insert open. Inside were LEDs wired to a circuit that turned them on and off in sequence. There was a spring-loaded microswitch to turn the contraption on when the magazine was opened. The whole thing was powered by six watch batteries, of the sort that would cost about three dollars each at Radio Shack. Needless to say, it was made in China.
I'd really like to know how much it cost the advertiser.