Hi,
Newegg has two (3.99 and 5.99):
Sunbeam FC PCI Fan Controller - Retail
newegg.com/Product/Product.aspx?Item=N82E16811992003
$5.99
ZALMAN FAN MATE 2 Fan Controller - Retail
newegg.com/Product/Product.aspx?Item=N82E16835118217
$3.99
Maybe one of those will work for you.
You could also look into building your own but I don't know the risk/cost/reward of that for you versus buying one.
Building your own fan controller.
silentpcreview.com/forums/viewtopic.php?t=22943
Make your own fan controller
custompc.co.uk/howtos/601285/make-your-own-fan-controller.html
Build your own temperature sensed fan controller
forums.hardwaresecrets.com/build-your-own/2598?
Good Luck,
Adrian