Once the domain of the military and mariners, GPS satellites have been available for consumer use for many years. I can still remember when the first ones hit store shelves, and many people wondered who would be interested beyond recreational boaters or hikers. Well, it didn't take long before companies steered toward the really big market: cars. (Of course, keep in mind if you do buy a handheld GPS, it can be used anywherenot just in your vehicle, though some are a tad bulky for walking around.)

Points of Interest
These days it's standard for a GPS device to have pre-loaded maps of the United States and all its roadways, a computerized voice that guides you and additional stuff like finding hotels, restaurants, gas stations, banks and local attractions (often called "points of interest" or "POIs"). It's simply a matter of typing in an address and following the audio cues and map.

Other things to consider include real-time traffic information, the ability to use your GPS device as a speakerphone, and storage for digital music or audio books.

Most GPS units offer a color touch screen, the chance to download newer and more maps, and the choice to switch between two- and three-dimensional views. Plus, you can always set what's called a waypoint, and then find your way back there if you decide to wander around.

What to Consider
The main considerations when buying one are just how accurate it is, how easy it is to update it with other maps and that pesky price question. Without testing one, it's hard to know just how accurate it is. So the best research is to find a model that fits your budgetprices range from a few hundred dollars to more than two thousand dollarsand read what others say about it. People get rather passionate about their GPS experiences and like to share their stories online.

If flashiness and lots of shiny colors aren't your speed, then just stick with the more rudimentary models. They'll do the trick and get you where you need to go. Those POIs do come in handy, especially in unfamiliar locales. You can search by name or type of establishment. Battery life can be an issue, but if you're in the car, the unit should come with a cigarette lighter adapter.

The bottom line is that GPS devices are intended to be accessible. All the big retailers carry some type of GPS unit, so always shop for the lowest price. Plus, GPS units will continue to get cheaper as more people buy into the idea.

Daniel Sieberg is the science and technology correspondent for CBS News.

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