My cap is 500MB in Canada, granted I'm not on 4G currently. Regardless, if you have such a low cap you probably aren't using your device for bandwidth intensive applications when on data, if I want to watch videos, etc. I wait until I'm on WiFi (and networks are available virtually everywhere, at least in Ottawa where I live). You can also reverse-tether your phone to a computer if there is no WiFi around.
That being said, I do disagree with the idea of data caps, looking forward to switching from Bell to Wind when my contract is up (as they offer unlimited data).