This is the cheapest set of lightbulbs I could find for a science experiment involving the Size of requires a flashlight Lightbulbs are cheap and burn out easily (kids found they could handle the voltage of 3D batteries, but more of them explode instantly) but they all worked when bought and performed good work at low voltage.
Lamp LED Xiaomi Mi Smart LED Bulb Essential (MJDPL01YL), E27, 9 W, 6500 K
113 Review
Ceiling lamp Yeelight YLXD013-B, 50 W, number of lamps: 1 pcs., color: white
62 Review
Smart socket Yandex with Alice, black
30 Review
Lamp LED Yeelight Smart LED Bulb 1S, YLDP13YL, E27, 8.5 W, 6500 K
43 Review