There are many places to get your PC games from but it hasn’t been like walking into the games store and picking up a physical copy of the game for a long time. Unlike the most common way to buy a game for a console PC games are generally bought as digital copies, this is great because as long as you know your login to the launcher you purchased the game from, you can download the game as many times as you like and never lose access to the game.
So where can you buy PC games from? So, as well as the very well known game launcher and store Steam, there are also a number of websites that sell codes that can then be redeemed through the likes of Steam and sometimes these websites offer games at lower prices than the official store.
The two main game launchers that I personally use are Steam and Epic Games. Steam is a great place to find a lot of games some of which are from budding creators and indie developers, Epic Games on the other has some fantastic exclusive content and also feature free games for you to download which change regularly. Just recently Epic Games were offering the simulation game Farming Sim 2019 to download and keep free of charge.
Just a quick word of warning though when using these key selling websites just be aware that sometimes there is a risk when purchasing from these sites, they do offer protection however in my experience with these sites adding on this protection sometimes pushes the price of the game over the retail price that the launcher is selling it for.