Does the iphone GPS use data?
 

I have the min att data plan, will the gps eat up my data allocation?

Most of the mapping is coming from the net, so that would eat data. If it is a standalone program or one that doesn't use maps, no.

It doesn't use a ton of data unless you are on it all day or trying to use it as turn by turn directions as opposed to a map. However, it absolutely kills the battery to use it as a true nav system with turn by turn instruction

The gps by itself doesn't use data. For instance, if you have an app that returns your current coordinates, it shouldn't use any data, but if you're using some sort of mapping app that always shows you location on a map, then downloading the map graphics will use your data.

I turned off everything, wifi, 3g etc and the gps still worked just fine and so did the maps I had saved from viewing before but it would not show maps outside my previous viewing area. Is there a map app you can download to use for gps stand alone only?

I don't know that there is or is not, but if there is, it'll be a huge download.

Get the AT&T my wireless app. It will show all data usage - test against that.