The cost of building an average PC can vary widely depending on factors like the quality of the components, the specific design of the system, and the labor involved in building it. That being said, a basic, no-frills PC can be built for as little as $500 to $700, while a more high-end PC can cost several thousand dollars. The key is to do your research and find the best components for your budget. There are many websites and resources available to help guide you in the process of selecting and building a PC that meets your needs and fits your budget.