These days, a new car is basically a computer with wheels. Trunks open automatically. The car parks itself. Rear cameras show you what you can’t see. If you lock your keys inside, you can open the doors by satellite.

The flashiest new gadget: a touch screen in the middle of your dashboard.

There’s a lot to love about these infotainment systems. Depending on the brand, you can organize your music, program the GPS and dictate text messages. Console screens are as wide as small tablets and they’re easy to read, even when you’re behind the wheel.

But there’s a cost: Many of these services require subscriptions for services like in-vehicle Wi-Fi hotspots, Sirius XM satellite radio and live traffic data. You may start with a free trial, grow accustomed to the conveniences and then find yourself paying fees later on.

These costs can add up over time, and the final tally might surprise you — especially when you set up automatic payment. You might not realize how much you’re shelling out for car-based infotainment until you look over your credit card statement.

How do you avoid getting caught unaware? Here are some preventive measures.

Grill the auto dealer

Buying a car is an ordeal. Even when we’ve picked our dream car, we tend to drive away from the dealership exhausted. (Tip in a Tip: If you’re hunting for a new car, there’s an app that makes it easy. Click here to find your perfect car. )

The last thing you want to think about is whether the console uses Apple Maps or Google Maps. But this is a critical time, because the dealer may want you to subscribe to as many services as possible. Don’t let salespeople confuse you. There’s no reason to sign up for anything on the first day. All enrollments are voluntary, and these apps will be available whenever you want them.

Infotainment systems are still new, and every car company has its own technology and services. Each system has distinct benefits and drawbacks: Volvo’s Sensus Connect has a touch screen you can use while wearing gloves. Ford’s Sync 3 uses a Blackberry-based system, and it’s a vast improvement on earlier versions.

Android Auto will appeal to Google and Microsoft users, while Apple CarPlay is designed for Apple fans. Your preference for Apple or Android devices will likely influence your next car’s make and model. On my site, I have information about both systems. Most importantly, click here to see which system is preloaded into different car makes and models.

A responsible auto rep will tell you all about these consoles and infotainment services. Ask how long the free trial lasts and how much the subscription will eventually cost. Grill them about cancellation policies, especially for features you’re not sold on. If any of these explanations sound fishy, just decline. Better to learn about your new car and drive it for a few hundred miles before adding features you may never even use.

Remember your smartphone

When it comes to vehicle infotainment, I don’t use any paid subscriptions. I use my phone instead.

The truth is, most upmarket cars come with USB or audio ports that let you plug your smartphone directly into your vehicle’s system. For years, tech-savvy drivers have listened to music on their phones and held hands-free conversations through their car’s radio and speakers.

An infotainment system is just a more sophisticated version of these radios and speakers. You can usually connect your phone directly to your infotainment console, which accesses all the music, podcasts, GPS, and streaming services you already have, and you don’t have to pay an extra penny.

There is one downside: Using your phone for navigation and streaming services while driving may devour your data plan. The same goes for “tethering” a device to your phone, a technique some passengers use to access the internet during commutes.

To avoid a data famine, you can download podcasts or audiobooks ahead of time, especially for long trips. It’s also a good idea to track your data use so you won’t go over the limit. For an app that serves this purpose, click here.

Looking for a podcast to listen to while you drive? Be sure to listen to or download my podcasts, or click here to find it on your local radio station. You can listen to the Kim Komando Show on your phone, tablet or computer. From buying advice to digital life issues, click here for my free podcasts.

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Learn about all the latest technology on the Kim Komando Show, the nation's largest weekend radio talk show. Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, free newsletters and more, visit her website at Komando.com.