$900 can get you a reasonable rig.
Laptops are stupid for a few reasons:
1. Gaming laptops are super big and heavy, so they really aren't that portable
2. Their performance is always inferior to a desktop
3. Generally there are no upgrades you can perform on them. Almost always opening the computer will void your warranty. Occasionally your warranty may not be void for RAM upgrades, but HD/SSD upgrades will void the warranty and cpu/gpu upgrades are impossible.
4. Their keyboards
always suck.
Pre-built desktops are also stupid, for a different set of reasons:
1. Very often gaming rigs are built with a massive cpu, like an i7 or something, coupled with a pointlessly small amount of RAM and a shitty gpu, often even just integrated graphics. This is because computer companies know how to exploit people who don't know anything about computers, and by putting a well known cpu in there these people are automatically attracted to it (it's called 'central' processing unit, it must be the most important part, right?). In reality your money should be split roughly 3 ways between gpu, cpu and RAM. This is a very rough guide.
2. Computers often ship with a 2 or 3 year warranty, and you will often find a seal on the door preventing you from opening the computer without voiding the warranty. This is the biggest scam of all that computer companies run, and all computer companies I know of do it. Their warranty may seem alright, but when you look at the individual parts, they often have much longer (~3 years to lifetime) warranties.
3. Knowing that you probably won't need to know what's inside your computer, computer companies will put cheap shitty parts where you might put a more expensive part from a reputable manufacturer. The companies never pass these discounts on, they just use it to further their profit.
The alternative to is you buy the parts and put it together yourself. This may sound like a daunting task, but once you look at it it's actually really simple. Building a pc requires neither electrical nor computational knowledge, all you have to do is follow instructions closely. Computers are designed to go together, so all building a pc is is clipping things into slots and screwing them into the case. It takes a couple of hours the first time, but it's mindblowingly easy.
Some of the advantages of building a pc are thus:
- It's cheaper. Almost always works out a bit cheaper, not loads though. Generally only enough to pay for a few games.
- You own the parts, you can change them how you like, you have their (significantly longer) warranties. This also allows you to break down the cost of building a pc - when I built mine I could only afford 8GB RAM and a 1TB HD, now I have 32GB RAM and a 256GB SSD in addition to the HD. I sold the old RAM, it depreciates fast but it takes a bit of an edge of the purchase.
- You get to brag about how you built your own computer, people who've never done it always think it's an incredible feat. It isn't, but they don't know. Warning: this does not make a good chat up line.
When I (and pretty much all of the internet) am designing a pc I always go to pcpartpicker.com. It keeps track of the prices for various retailers, and has a compatibility filter to make sure I'm only buying parts that'll fit together.
Here's a $500 build that comes almost straight from r/pcmasterrace, they name it the 'next gen crusher' because it outperforms the next gen on benchmarks. I've made some changes: RAM doubled from 4 to 8GB, added a third party cpu cooler because AMD ones sound like concord, added a 256GB SSD because they're quicker than HD's (install the OS on here), also Windows 8.1, a monitor and a decent keyboard and mouse. In total comes to roughly the price of a decent game (in steam sales) less than your target $900.
Here's the link:
http://pcpartpicker.com/p/XZ7xCJ
Also here's a youtube video on building a pc:
