[btonetbone]

Using standard GPS does not need data and should work just fine.

However, programs such as Live Search and Google Maps need to access data in order to download maps. Programs such as Garmin and Tomtom store the entire maps on your SD card (upwards of 1 gb of data) and do not require data.

Enabling aGPS (discussed in some of the threads here, where you download a program called QPST to your computer and adjust some deep settings on your phone) will cause GPS to use data, so do not enable that unless you get a plan.

Hope that helps!
Ivan