I need help with (basically everything) to build my first computer

     Pretty much everything I need help with will be said on this topic
So I'm 14 and I"ve been hooked on the idea of building my own computer since when I was about 8.
I"ve been playing PC games (TF2 mainly) for a while now but in the past year a bunch of stuff has happened to our computer situation and I"ve been pretty frustrated with our computer (especially since I"ve bought 8 games during the steam summer sale ) Our first one's motherboard broke, the one after was crappy and borrowed, and now this one is relatively new but it's pretty bad and freezes and the I can barely run Tf2 or Gmod multiplayer.  My mom knows I want my own computer and she's talked about it and all so now is the time.
                 
          But I'm just rambling, I"ve been saving up money and I have around $200 and my mom said that she is willing to chip in and help by buying a desk and monitor with my Christmas money. I'm not sure how much money I'll have by Christmas time to buy my computer but I need help finding a computer that will give me every penny's worth that I put in it. I"ll say around $400 maybe a bit more by Christmas time. I also need to accommodate for putting windows 7 on it and also a monitor that is compatible for it. I would be able to find a build online but I don't have enough in-depth knowledge about the specifics of CPUs and GPUs to find out what is more upgradeable and compatible with what. There is so much to know that I'll never be able to just go on Tiger direct and pick out my parts and buy it right there. 
               Sorry if you hate reading so I tried to make the actual question stand out but I tend to go on and on and on.

Did she talk about a budget?

Wow that was fast. No, we only went as far as her asking about gaming laptops. And then when I scared her she told me that she was thinking of chipping in with Christmas money to help with getting the computer.

get a budget and hollar back... preferably something $600+ for a desktop... that'll get you a decent AMD rig... for Intel, you're looking more in the $800 range

I'm not good with asking about stuff with lots of info so I'll message her and make sure to include about a budget

No need to include a lot of info... msg "Hey, about that computer we were talking about... any idea of a total budget not including the desk?" ... just note with less than $600 in your tower, you're going to be skimping on really necessary things... I'm not saying you can't build one for less than that (you can build one for $300, it'll just suck)... but you'll likely be disappointed with the performance...

I just want to be able to run whatever I already have (Tf2 Gmod CS:S) and it have decent fps on..even medium settings. I only want a stepping stone to build on, no LPC. lol

gotta watch a show n I'll be back in an hour and build a baseline for you... bbiab

The main things we need are:

Budget(as DrunkenPanda stated)

Country

Anything not tower-hardware related(e.g.: operating system, monitor, mouse, kb, speakers, etc)

The os will be windows 7, idk about the monitor yet, the peripherals will mostly likely be from a friend who has spare stuff lying around. The speakers will just be from the monitor, I already have a headset and if I change my mind and want actual speakers than I can get $20 ones from the Walmart. I live in the US btw.

I'll put up this build to get things going its just under $600

http://pcpartpicker.com/p/JhTFbv

Not much sense to put a 750w power supply on an FM2 system.

Try this: http://pcpartpicker.com/p/mzjvdC

I put the 750W in because it was $60, your build works too but I'm not really feeling that board though (AMD on Gigabyte boards has not been a pleasant experience for me) so I'd go with a M5A970 R2.0

http://pcpartpicker.com/p/jW7M4D .... my $600 baseline gaming budget build... (FX 6300, R9 270, 1TB HDD storage, 8GB memory, decent case for cheap, 500w PSU, and Noctua CPU cooler... 

I say baseline, being that it's the least amount of performance *I* would do a rebuild with... you could go with a 760k, you could do a lot of things different... but this is what I consider a decent budget gaming pc...

http://pcpartpicker.com/p/6zsM4D .... $675 with better GPU, less suspect PSU, color matching ram, 

http://pcpartpicker.com/p/vwFC4D ... $750 with SSD

http://pcpartpicker.com/p/hW7M4D ... $800 with SSD, 8-core, better mobo

Highly recommend this monitor for price/performance... http://pcpartpicker.com/part/benq-monitor-gl2460hm .... 1080p, 24", 2ms response, LED.... you can't beat $130 for that...

Keep in mind that prices fluctuate daily... if you aren't buying till Christmas you might consider purchasing parts as they go on sale... you'll save money... I'd recommend the Corsair Force LX Series, MSI R9 280, and NZXT H230 as parts to pounce on with the rebate... not really in that order, they're just good buys of quality parts that I haven't seen that low in a while that won't be outdated by Christmas...

If you're set on an Intel option I could post one, but it'll eat your GPU upgrade for computing performance (which you don't need as a 14 year old :P)

and email me: [email protected] ... about windows 7 ;)

Ah, fair points.  I also have MIR turned off on my PcPP, so it came out to be kind of expensive.

It's fair to have MIR turned off... I NEVER send them in... like... ever... free money, and I refuse to claim it :(

I do hate gigabyte AM3+ mobos for reason I'm sure you've already read though... (BIOS, and that humbling experience I had)

I've just been looking through all the newegg reviews and they pretty much praise this board for being able to handle FX-8350s just fine.  I do wish I could test it myself :(

Its the awful UEFI that kills it for me

That "classic" UEFI that was shown it the Z97X-SLI review that wendell did, that's the standard UEFI that's on all non G1 AMD boards and its pretty dreadful (missing tooltips, missing settings, and other really strange things), oh and my motherboard's PS/2 port is non functional straight out of the box

I will be getting an Asus Crossblade Ranger when it comes out and I'm gonna sell my current board, I'm fed up with Gigabyte

maybe rev 4 fixed the issue... but that 8+2 was the sale point for one of my builds at the company... and my owner nearly quit letting me build computers on that particular build... I'm not sure if it was THAT particular mobo... but I will never recommend Gigabyte AM3+ with a passion...

I see a lot of people on here had better experiences, so it is what it is... but Jesus... 3 DOAs and a blown capacitor on the one that booted like 3 weeks later is enough to make you hate a company... especially when they charge you both ways for shipping...

I'd just rather have the digi 6+2 power phase, WAY better UEFI, and no DOAs on 30+ Asus boards I've put together... it's personal experience biased...