Charging for Christmas light installation depends on a variety of factors, such as the type of lights used, the complexity of the installation, and the time and labor required. Generally, you should charge by the hour, with rates varying based on the location and experience of the installer. For a basic installation, you may charge between $50 and $100 per hour, while more complex installations may require $100-$200 per hour. Additionally, you should consider any additional expenses such as travel costs or materials. It is important to be transparent and upfront with customers about your pricing structure.