PC building has a learning curve, but the most important thing is to not get too hung up on figuring out every last detail. With that in mind, focus on what you want your PC to do and how much money you want to spend. You can spend as little as $300 to build your PC. Some of the components will be more expensive than others, but it’s up to you how much you want to invest in your machine. For example, a CPU can cost as little as $300 or as much as $1,000. (Note: CPUs are often the most expensive component.)