I currently have a mini tower containing an SSD, one 2TB HDD and one 3TB backup HDD. Thanks to this Stack site, I recently installed an Arctic Freezer 11 LP for a CPU cooler, which is now the only fan in my system apart from the one on my Corsair VS550 PSU (which faces backwards, towards the rest of the components).
I feel like I need an exhaust fan in there just to offset the high temperatures of my drives, the SSD in particular:
However, I know very little about coolers, so I'm unsure whether a back exhaust fan would be installed to the inside or the outside of my mini tower's back grill. If it's the former, then as well as fitting in the case's back grill size of around 10 CM/3.5 inches, the exhaust fan in question would also need to have a depth of less than one inch to prevent it colliding with the Freezer 11 CPU cooler.
To add to the conundrum, I'm on a low income, so the cheaper the proposed fan is the better.
TL;DR: I'm looking for the cheapest, quietest low-profile exhaust cooler that will fit in my PC.
Would really appreciate some help with this one, I understand there's a lot to consider.