I have received some questions similar to this over the course of 2 or so years. It comes up quite regularly for those just getting into the hobby of PC building, upgrading, and gaming. And it should, quite honestly, because it is a huge concern even for those already owning good computers.
Let’s run down some basic costs to see what you could get away with for gaming. Note that these are just for being able to generally play video games. A lot of gaming rigs out there are designed to be able to play PC games on high settings for many years, and many build out their computers in anticipation of higher mainstream technology. For example, building a computer with a ~$500 graphics card, like the GTX 1080, is supposed to let you play games on at least 1440p at high settings for the foreseeable future. But those are the exceptions to PC gamers, as oftentimes we are just content enough to be playing games like Counter Strike: Global Offensive, League of Legends, and the occasional single player experience like Dragon Age: Inquisition or what have you. Of course, graphics matters, but the ability to just have our foot in the door is enough, as we are able to upgrade later when we have the money.
A gaming computer will run you at the bare minimum roughly $400 to $500. Prebuilt computers at this price range typically are enough to play most games, some even released this year. But for the most recent games, you are pretty much limited to playing on low to medium settings at 720p or at the most 1080p. Still, it is good value if you want to get your feet wet with PC gaming, and it is pretty inexpensive. You can also build your own computer for that price range. I actually built a computer with no graphics card, just a decent processor in the Intel Pentium G4400, 8 GB of RAM, and an SSD. The computer itself cost no less than $299. I already had a monitor and accessories to accompany the computer, but still, the budget on this PC was very limited. Even with that money restriction and not having a graphics card in place, I am still able to play CS: GO on high settings, and consistently get 60 frames per second. Other games work well too, including Team Fortress 2. Adding an extra $100 or so to the budget will allow you to place a graphics card in there that will surely let you play more decent games at medium settings.
Your accessories are going to cost you as well. But if you just want the basic keyboard and mouse, as well as a simple USB audio speaker set, you can save yourself a lot of money. For my budget build referenced above, I paid for the Amazon accessory bundle, which comes with a basic keyboard, a basic 3-button mouse, and some simple speakers. The bundle cost me around $25, which is around half the price you’ll see for just one mechanical keyboard. Clearly, these accessories are at the most basic level, with no additional functions to make it easier to game for you nor do they have any cool backlighting, but they get the job done. I assure you that you can still play video games without needing an expensive gaming mouse, keyboard, and speaker set.
After building or buying your computer and setting up your gaming accessories, the last step is buying the actual games. A lot of times, some of your PC components will come packaged with a video game as part of a bundle/promotion. I know Newegg loves to do these with many of AMD’s RX graphics cards as well as some older GTX cards. But if you do not get a game bundled in, which is the most likely scenario considering we are only discussing the most basic costs of gaming on the PC platform, then you will get started on Steam. Steam is the biggest digital PC game vendor in the world, and most gamers turn to making an account and playing most of their games on their platform. They offer many daily deals and their seasonal sales have plenty of steals as well. Other vendors include Amazon (great for physical copies), Best Buy (also good for physical copies if you have Gamers Club Unlocked), EA Origin (EA’s version of Steam), and Blizzard’s Battle.net app (the platform for Overwatch, Hearthstone, Diablo, and more from Blizzard).
In all, PC gaming gets a bad reputation for being expensive. Sure, you may end up spending a lot more than you would on console just for the machine. But the value is definitely higher, considering you can build your own computer for the same price as a console (~$400) and get more power from it. On top of that, digital games are much cheaper than console games. The point is that PC gaming is not as expensive as people make it out to be.