Cheap, over 24 hours?

Dollar Store.

https://www.dollartree.com/Luminessence-Flameless-LED-Emergency-Candles-2-ct-Packs/p357708/index.pro

LED candle- the shorter 2 battery ones do no have that fake flicker. 50 hours on 2 AA, the pack includes 2 lights.

I have a 2 pack in each of the kids camping bags as tent lights.