Less expensive, but I am sure it is the same fans.
What you are paying for is a fancy housing and thermostat system as well as (depending on which of the fancy ones you look at) exhaust to the front or rear. If your units will be in a cabinet without a lot of space to the shelf above the AVR, you would want to be able to direct the air out of the front of the console (I am assuming no doors).
This one ($40) requires you cut a hole in the cabinet wall to mount it (and drill intake holes). Adding a thermostat system increases the price to $70:
This one ($110) exhausts to the front and has a sophisticated thermostat system:
This one ($15) is a simple one. It is just two 80mm fans mounted on pretty good shock absorbing feet with a two speed (plus off) switch:
Just go to Amazon and search for "AC Infinity fans". They have a lot of great options!
These are not dead quiet, but if you run them on low, they are not bad. I really don't notice mine turning on because the audio from the system covers the noise from the fans.
With the sophisticated thermostat setup, I set mine to come on low at something like 85 degrees F and switch to high if the temperature gets above 95 F. Happily, the low speed does the trick and things never get hot enough to kick the fan into high speed!
Based on my experience using the simple $15 dual fan system, just leaving them on the low speed works great!
