How much data does maps on my iPhone 4S use?

I am a Canadian headed to the states for a road trip. I'll only be in the states for ax 3 days but I don't have a GPS and was looking to periodically use my iPhone as a way to help not get lost. My service provider has different data plans for the states but I can't decide which one to go with until I know how much data my iPhone will use with JUST the maps on.
Also, does Google Maps use less or more data than the maps app that comes with iOS6?

You won't be using much at all just download the map before you go on your trip you can save maps on your phone