Nobody said anything about AA batteries. Those are D cells. But AA would work.
As long as you match the voltage to the light bulb it doesn't matter. If you can come up with a 9 volt bulb, you could carry one of those little rectangular 9 volt batteries.
The 3 volt bulbs are the most common. Almost everybody has a couple old two cell flashlights laying around with the switch shot and the bulb still good. You might need to go to the store for the alligator clips though.
Endeavor to persevere.