PC fans are cheap, quiet, consistent, and abundant. Compared to fans you can buy retail on normal house AC circuits they are superior in every way. I will guide you through the easiest way to run one.
get a free ride off of a different device's power cord (free)
or dedicated power cord Scrap(free hopefully) else 1 - 3 $
solder, heat shrink, elect tape, etc (cheap)
total: 2$(scrap fan + power cord)
total: 7$(all new)
Step 1: Pick Your Fan
From your fan we need to confirm the Voltage, Current, and Circuit type. For most pc fans it will be 12v DC and you just need to get the current rating.
The fan i used is from ebay:
Circuit type: DC
Current 0.36A ( 360mA )
Step 2: Pick Your Driver
So i need to convert my AC home circuit 220v / 110v to 12v dc
Now we want to use a current limited power supply that gets close to 12v and is close to 360mA
These are usually marketed as LED drivers, or transformer for LED strips. Need to make sure they are very close and not exceeding the fan current rating(this kills the fan) also max voltage should be12v or less.
Step 3: Hook Them Up!
Red to red, Black to black
If using one fan, its easy just make sure you hook up fan to output marked on driver... and input into a power cord that plugs into your house outlets.
If hooking up multiple drivers (say you want to hook up fan with your led lights driver) to one power cable, do it in series.
If using more than one fan on your single driver hook them up in series, + to - + to - make a big loop.
Here it is running:
Here's another one: