I only pay for the 200MB per month plan from AT&T, so I always use less than that.... The plan determines my behavior, not vice-versa. I'm careful to turn on W

I only pay for the 200MB per month plan from AT&T, so I always use less than that.... The plan determines my behavior, not vice-versa. I'm careful to turn on WiFi both at home and at work. I can't allow myself to listen to streamed music in the car. And I have installed DroidWall (a firewall app for rooted Android phones) and blacklisted certain "chatty" apps from using the network over 3G.