I am looking to buy 3 more fans (that is all the slots left available). I do not want to spend a lot of money, $30 max for all 3 if that is possible. I want to get two fans for the top of the case, and one more in the front (already has one). The two top ones can be 140mm (all of them are 120mm). I want to improve my cooling, but not make it too loud. I am just looking for advice on cooling and what fans to buy. Thanks!