This is my entry level Build to my video-guide on How to choose parts for a gaming PC. Sadly there are no pictures for this, because I didn't yet have the opportunity to build it. I'm gonna link the Parts on Amazon at the bottom of this article, PCPP often doesn't get the prices right and you can support me by buying parts over those links.
This Build is build is particularly centered around beeing affordable and easily upgradeable without sacrificing looks.
Without changing anything else you could up or downgrade the GPU, upgrade the Processor and increase the RAM.
The Ryzen 3 2200G is a APU, so it would work without a GPU. So if you really urgently need a PC, that might run Fortnite you can build this without the GPU for around 400$.
Even though its entry level, this CPU won't bottleneck a RX 570 or even a RX580.
If you're out for a bit more longevity, you could up this this to a Ryzen 5 2600.
I also could have chosen an Intel i3, but the Ryzen 3 is cheaper and comes with a better cooler (next to beeing an APU).
The RX 570 is still the probably best Bang-For-The-Buck Card around. It will let you play everything you through at it in 1080p, even though at sub 60 FPS in more demanding titles.
If you have a little more to spare, get a RX 580 or 590, but then you already might wanna look for something like this Mid-Range Build which actually looks quite similiar.
I've chosen the Sapphire Pulse 8GB because its the first and cheapest RX 570 that comes with a nice looking backplate. It totally won me over in the aforementioned build, both in performance, design and quality.
The Asus Prime B450;-K is a quite basic board that will allow you some overclocking, offers nice fans controls and a little bit of RGB. Asus boards allways have great quality and the IMO best UEFI.
As mentioned in my Video I'm really fond of the G.Skill Value RAM. They are cheap, look clean and G.Skill has great Quality. When you're getting a single 8GB Module you can easily upgrade by time to 2x 8GB. If you have a few bucks more or upgrade your CPU/GPU you will want to get atleast 3000MHz RAM, like G.Skill Aegis.
Storage is kept at the minimum, even though you might be able to go for a 120GB and 500GB HDD but I don't think this would be worth it.
The Masterbox Q300L looks clean, is cheap, very flexible and easy to build in.
Because it doesn't have a PSU shroud I would recommend to get the Modular PSU Version to keep the look as clean as possible.
The Masterbox only comes with one Fan at the back. I'd move that to the front and install the Corsair ML120 in Red or RGB in it's place. It's probably the best (looking) Fan and easily bright enough to illuminate the whole case.
Here are the aforementioned Amazon Links (DE/UK/US):
Ryzen 3 2200G https://amzn.to/2Vwe5qS | https://amzn.to/2Rd2gYd | https://amzn.to/2LXHGFr
Ryzen 5 2600 https://amzn.to/2ABYUnk | https://amzn.to/2RgK5kf | https://amzn.to/2AAvuFU
Asus Prime B450M-K https://amzn.to/2CXwaak | https://amzn.to/2VC25UR | https://amzn.to/2CaVpUT
G.Skill Value 8GB https://amzn.to/2CaUCD8 | https://amzn.to/2ACBBcU | https://amzn.to/2VEWmgV
Kingston A400 240GB https://amzn.to/2Canzzd | https://amzn.to/2ACOpAe | https://amzn.to/2Vxx8Bj
WD Caviar Blue 1TB https://amzn.to/2TBvvAF | https://amzn.to/2H3ApoA | https://amzn.to/2SFCR64
Sapphire Pulse RX 570 https://amzn.to/2RiUFaw | https://amzn.to/2VDpaGM | https://amzn.to/2C7jM5K
Sapphire Pulse RX 580 https://amzn.to/2VKQi6S | https://amzn.to/2H0ADNb | https://amzn.to/2CVKNuC
CoolerMaster Q300L https://amzn.to/2Rkgh6n | https://amzn.to/2RE7aNc | https://amzn.to/2VDi45d
Corsair CXM 450W https://amzn.to/2C6EPFD | https://amzn.to/2GZn3JW | https://amzn.to/2SJdSyK
Corsair 120ML120 Pro LED https://amzn.to/2ABclUp | https://amzn.to/2ABcJ5j | https://amzn.to/2RE9sfg