The cost of installing Christmas lights depends on a number of factors, including the size and complexity of your home, the type of lights you want, and the length of time they will be installed. As a general rule, it costs around $500 for a professional installation of basic lights, but it can go up to $2,000 or more for more intricate displays. Of course, it's always best to get a quote from a local installer to get a more accurate estimate.