Last year I ordered a gaming PC from Cyberpower, which for the most part I'm very happy with. The problem is that it overheats like a mother, to the point where I'm better off leaving the side panel off and using a desk fan. I'm 90% sure it's because of the way the case is designed. There's a front fan, but no open space on the front for air to flow through. The side fan has a plastic grid over it that has to be cutting down on air getting in. The rear fan has the CPU's liquid cooler radiator screwed to it, but overall it's in a good spot/only has a standard metal mesh over it. More specifically, this is my case: http://www.newegg.com/Product/Product.aspx?Item=N82E16811144253 That said, I'm thinking it would be a good idea to get a case with better airflow and am looking for suggestions. For price I'd prefer sub $50, but am willing to consider a little higher.
I have used this case http://www.newegg.com/Product/Product.aspx?Item=N82E16811119259 for a number of builds at work, a little more than the $50 you were looking to spend, but I love the layout and it is built pretty solid.