I have this one -
http://www.truckcustomizers.com/prod...4REE682.1.html
I paid about $50 and it works really well. I don't have all the fancy readout, but I don't think I need it either. It works the brakes and that's all I want it to do.
Here's one at RVBusters and you may find them for less on eBay.
Just looked it up and here's one on eBay that is only 18.00.
http://cgi.ebay.com/ebaymotors/NIB-R...spagenameZWDVW