I have one of the Navigon GPSs for my car. I love it. I think it's one of the older 2100models, but I got it for right around $100. What I love about it is that, as you're approaching any freeway/tollway exit, it shows you which lane to get into. I've added lifetime traffic support also. You can usually find them for around $30 online. The only bitch I have with Navigon is that the map updates are $50.
What kind of cell phone does she have? She could look at getting Bing for Mobile. Comes with an ok GPS.