Fort Worth Public Library asked me to do some research on Gate Counters. In my research, I quickly found out that most vendors call them People Counters. The price range I found was between $130 to $600. I did not find any reviews on any of them so I welcome comments on what is best. Here are three vendors I did locate.
People Counters, Laser Electronics, http://www.thepeoplecounter.com/Order/order.html
Entry Level People Counters, SenSource, http://www.sensourceinc.com/peoplecounters.htm
Walker Wireless People Counters, Walker Wireless, http://www.walkerwirelessco.com/cgi-bin/catalog.cgi