Good gaming PC that lasted for about 4-5 years, with only updating it with RAM or another graphic card for about 250 EUR, costed me each time around 1000 EUR, normally a bit less then that. Instead of ordering already fixed PCs at a media-shop, try to find a small shop, where they talk about you, with what you want to do with your system, how you use it, what type of games you play...
Because of that they dont need tons of stuff you dont need, and the money you safe, you can use on the stuff you like.
As example, my Gaming PC has a real small memory-space in comparison to "complete to buy PCs" because of me not doing anything like keeping hundred of movies, tons of photos and private videos... I need enough memory for about 4-5 games I actively play and some extra for some spare photos I have or private documents, but thats it. Most "ready PCs" also have Microsoft Office on them, that costs about 150 EUR license. For what I use my PC the free downloadable openoffice is completly sufficient. Additional if you wait, when a new generation of graphicard is released, so when there is a new technic that raises the power of the praphic cards by an certain amount, the graphic cards that has been quite expensive topmodels before, decrease in prices about 40%, because of the companies wanting to get their storage free of them for the new graphic card models. On a "ready PC" you often have programs for videoworking or photoworking included, that I simply dont need, but that need small license payment. I also dont have that typical slots for all kind of photo-memorycard-reading, I simply dont need it. I also dont care for colourful PC-suits with LEDs or such stuff, I always care to have a medium standard shell so that I dont need to care for how much space I have left, if I want to give in another graphic card. Because of me always playing with headsets I also dont care for a silent watercooling and so on. My PC is according to its noise quite a hoovercraft ^^, but with headset I dont hear it anyway, I only need to care to remove the dust and cathairs that comes in from the ventilation, from now and then.
So all of this stuff, only save you a little money, 150 EUR for Microsoft office, 50 for a grey boring shell instead of a black extra small with some LEDs, 20 EUR there for the nonexisting photocardreaders, 80 EUR here, 35 EUR .... but in the end I aways had a real good gaming PC with brandparts (not the exterior but as example there is much you can do wrong about saving 5 EUR for RAM-sticks), that I was always happy about for a maximum of 1000 EUR. There are people that are willing to pay the double-price for a really brand-brand-supernew PC...but thats technical normally only three months more advanced then the systems I buy, so its a complete waste of money out of my oppinion. ^^ So my PC its really "naked" when it comes to everything else...but its gaming job it does quite well, and for Email-reading, Internetsurfing and opening my .pdf online telephone bills, its also sufficient. ^^