[Build help] Is it possible to build a computer on a $300 budget?

Hello, I was looking to buy a new PC today and realized how much of a rip off it is to buy a complete tower in stores. I've never done this before so bare with me. Im on a budget of around $300. I need a computer to do work and research on but can also run MMOs without being super laggy. Am I asking too much for $300? Thanks