I used this cooling system to keep my old bass amp cool for outdoor gigs in the summer. It is thermostat controlled and programable with movable temperature censors.
$100
read more on it here ProCool SP480x
http://www.rackfans.com/modules.php?name=ProCooL_SP480X
$100
read more on it here ProCool SP480x
http://www.rackfans.com/modules.php?name=ProCooL_SP480X