Looking to get a pc for gaming and would really like some help! My budget is around $400 for everything I need.

Solution
no way to do that new but here is a used build that could work for you
x5667-40$
dell t3500 mobo-40$
3*2gig ram- 24$
r9 280x- 150$
t3500 psu-45$
dell t3500 front io panel.
linux- free
case- just get the cheapest possible
ok here is a pc for 500$

CPU:http://www.amazon.com/AMD-FD6300WMHKBOX-FX-6300-6-Core-Processor/dp/B009O7YORK/ref=sr_1_1?s=pc&ie=UTF8&qid=1453301362&sr=1-1&keywords=fx+6300
GPU:http://www.amazon.com/MSI-GTX-950-2GD5T-OC/dp/B0147ELTUO/ref=sr_1_10?s=pc&ie=UTF8&qid=1453300825&sr=1-10&keywords=gtx+950
MOBO:http://www.amazon.com/ASUS-Micro-Motherboard-M5A78L-M-USB3/dp/B00DQO9L1Q/ref=sr_1_7?s=pc&ie=UTF8&qid=1453301362&sr=1-7&keywords=fx+6300
RAM:http:http://www.amazon.com/Kingston-HyperX-FURY-1600MHz-DDR3/dp/B00J8E92R6/ref=sr_1_6?s=pc&ie=UTF8&qid=1453301935&sr=1-6&keywords=hyper+x+blu+4GB
storage:http://www.amazon.com/Seagate-Pipeline-3-5-Inch-Internal-ST3500312CS/dp/B002CMOH26/ref=sr_1_1?s=pc&ie=UTF8&qid=1453301777&sr=1-1&keywords=hd+500
PSU:http://www.amazon.com/EVGA-Continuous-Warranty-Supply-100-W1-0500-KR/dp/B00H33SFJU/ref=sr_1_1?s=pc&ie=UTF8&qid=1453301134&sr=1-1&keywords=500w+psu
Case:http://www.amazon.com/Rosewill-Micro-Tower-Computer-SRM-01/dp/B00ZPWOA6I/ref=sr_1_7?s=pc&ie=UTF8&qid=1453301159&sr=1-7&keywords=rosewill+case&refinements=p_36%3A1253504011
TOTAL COST:436 without OS 😀 you can find windows keys on reddit for 10 dollars or a little bit more, or just use linux ,it's free and opensource 😀 :) don't forget best answer 😀
 


first the build i suggested will preform about the same for less. and i wouldn't advise linux on a gaming computer