1. Trapster

Pros: Uses iPhone GPS to determine proximity to speed traps, speed cameras, and red light cameras; audible warnings even when iPhone locks itself; users can easily report speed traps.

Cons:Red light and speed trap warnings can sound off too frequently.

The gist: Short of using a radar detector, Trapster identifies hazards to your driving record through an active community. This type of information used to travel by word-of-mouth, but Trapster makes it readily accessible.

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2. Cheap Gas

Pros: Lists fuel prices at specific gas stations around your current location; tapping each entry displays prices for regular, unleaded, premium unleaded, and diesel.

Cons: Button to map each gas station doesn't work properly; fuel prices may not be up-to-date.

The gist: Being able to find the cheapest gas within your proximity at a glance will save you quite a bit of money over time. Cheap Gas is especially useful in unfamiliar areas.

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3. Take Me To My Car

Pros: One-button interface for marking car location; interfaces with Google map app for directions, can be used to mark locations other than parked cars.

Cons: Can only mark one location at a time.

The gist: There are many apps for finding parked cars, but Take Me To My Car is free. And how many features do you really want in a simple car finder?

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4. RepairPal

Pros: Includes useful tips with repair estimates; local repair shop search specific to car makes; one-touch access to roadside assistance.

Cons: Model years before 1990 not represented.

The gist: RepairPal is useful when you've got a breakdown, giving good advance knowledge of what to expect from the repair bill.

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5. PocketDyno

Pros: Two modes to start a timed run; shows 10 mph increments leading up to 0 to 60 mph time; calculates horsepower.

Cons: Free version filled with nag screens; need a stable mounting bracket for accurate statistics.

The gist: PocketDyno is the cheapest performance computer you can get, as long as you already have an iPhone or iPod Touch.

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