The DigiQ is not exactly cheap, coming in at just under $200 with the blower and adapter.
If you're inclined, you can make a version of Bob's Controller with a fixed setpoint and without the LCD or WiFi pretty economically.
$20 Arduino Pro 5V/1MHz
$2 MOSFET
$2 probe/fan jacks
$1 diodes
$1 resistors
$1 capacitor
$14 blower fan
$10 project box (or just use any other plastic box you have lying around)
$41 if you use your own box, plus some wire and solder.