TomTom does its map updates via a service called TomTom map update service. This service charges you an annual fee, and then gives you one free update each quarter. This means that you get four map updates in each calendar year. The advantage to this is that you can also create your own custom updates. This means if you want to report a temporary road closing or a local point of interest your GPS will remember it. Though, there are also some free maps.
Garmin’s updates are done via disk. You buy a disk for your specific region, (North America, Europe, South America, etc…) and upload it to your GPS. These disks can cost up to 70 dollars.
Magellan also charges for updates to your GPS’ maps. The Magellan updates are varied in price, depending on your needs.You can however sometimes get a map with a software upgrade.
Not the big three
If you have a GPS that is not made by one of these three big boys, you will still need to update your maps. Here are listings for some of the smaller brands of GPS.
Navigon uses a service known a Fresh Maps to update its GPS maps. This is a paid service. It is worth the mention that despite the fact that Navigon has pulled out of the US market, they are still supporting US map updates.
Mio's map updates are free in 2009 for Mio. They have not said if the updates will continue to be free of charge.