Most of the time the Graphics Card is by far the most expensive computer component. However, the reality is that not everyone needs an expensive GPU. Usually, it all comes down to what you are using the computer for and what features do you need from it.
What activity do you want to use it for?
If you want to use the graphics card for gaming, you need at least one around $300 or $400, as those tend to offer enough power for quality gaming. However, if you’re just a casual computer user a $100 - $200 graphics card will be more than ok for you. The idea is to understand that you just have to spend a lot of money on the graphics card when you actually need to do so. Try to avoid spending way too much on the graphics card if you don’t play games or use graphically intensive programs.
How many monitors do you have?
Expensive graphics cards are required if you have more than a monitor. The same thing happens if you have a very high refresh rate on every monitor. And yes, if you have a 4K monitor then you do need a very good GPU too. All these things tend to require a lot of processing power from your computer, so try to keep that in mind if you can.
You also have to see what your computer is ready to accept. Very powerful graphics cards tend to require a lot of Watts, so you need a very good power supply unit. In addition, if you have an old graphics card slot such as AGP, you are limited to very specific graphics card types. You need to figure out every tiny detail to avoid incompatibility problems.
What games are you playing?
If you want an expensive graphics card, you most likely want to use it for gaming. However, what games do you play? The latest shooters like Battlefield V or Call of Duty Black Ops 4 require top of the line computers. On the other hand, games like DOTA 2, Rocket League and Overwatch run on older computers too. So you really have to take your time, create a list with those games you want to play and see if you really need a very powerful computer. If your games are not that demanding, you won’t require an expensive graphics card.
Let’s face it, every person has different requirements from a graphics card. Ideally, you don’t want to spend too much on a graphics card unless you play some of the latest games. If you’re just a casual gamer, a $200 graphics card will be more than ok. And if you don’t play games at all, you just need a graphics card powerful enough to sustain a monitor or two, depending on what you need. However, if you are a video creator, you do need a powerful graphics card for rendering.
You don't always need GPU to operate your PC as GPU just adds bonus performance. So if you are not sure what to buy you can always add it when you know the best GPU for you. It all comes down to your requirements and needs.