Running Christmas lights is a relatively inexpensive holiday expense when compared to other holiday-related costs, such as gifts, decorations, and travel. Depending on the length and complexity of your light display, the cost of electricity can range from a few dollars per month to a few hundred dollars per month. Additionally, there are many ways to reduce the cost of electricity by using energy-efficient LED lights, installing timers to control when the lights turn on and off, and using solar-powered lights in areas with ample sunlight.