CPU Cooler
An important part of keeping your PC air flow regulated is the cooler. Without a cooler your PC will overheat and ruin your other parts.
Sometimes your CPU will come with it's own cooler. This is generally fine for basic PC builds. However, if you want a better PC build it is best to get a separate cooler. A PC cooler is device that draws heat away from a CPU chip and other hot-running chips such as a graphics processor (GPU)
The main types of PC coolers are Air and Liquid cooling. Liquid cooling is the better option if you are going for high gaming PC. However, even with a gaming PC air cooling is completely suffice. In high end gaming, liquid cooling can be 2-10 times more effective than air, it all depends on what build you are going for.
If you plan to use your PC for schoolwork and low gaming, go for air. If you plan to use your PC for higher end gaming, get a liquid cooler.
Air Liquid