Like lazerman said any thermaltake case does cool very well and for the budget that you said well maybe you should save a few bucks and get that better case or look around some more.
Keep in mind though if you order from newegg shipping is normally not much if anything. so you could maybe get one of the cheaper coolermasters like this one http://www.newegg.com/app/ViewProductDesc.asp?description=11-119-038&depa=1 which will do a good job but keep in mind it has no fans so you will have to dish out a little more money for fans.
if you get that cheap case i listed in my first post (the real long one) and replace all the fans with new ones it will still be well under $80 and cool your system well.
Ok this is my last option for you its a couple of bucks over 80 but this thing will definetly cool down your case really good. Lots of fans prefect gamer pc to. No side window thought.8-( but read the review.