8 of the biggest scams to avoid when buying a car

• Buying a car can be stressful, especially if salespeople are trying to run a scam on you.
• Alan Diaz, a branch manager for Cartelligent, listed eight of the most common scams you might encounter at a car dealership.
• If a deal seems too good to be true, he said, it probably is.

Buying a car from a car dealership can be a stressful experience.

It's even worse when the dealer is trying to run a scam on you.

Your best defense is to arm yourself with knowledge before you go car shopping, according to Alan Diaz, Southern California branch manager for the car-buying service Cartelligent.

"If you plan things out and give yourself some time, it will pay off drastically,” Diaz told Business Insider.

Although the internet has leveled the playing field — "you can google info on the spot," he said, and "dealers have to be better"— you should still be on the lookout for questionable tactics and deals that seem too good to be true.

Here are eight of the biggest scams Diaz said dealers try to pull when you're buying a car.

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Hidden costs for new cars

"Price is not everything," Diaz said. "There could be underlying costs which, in the long run, cost you more than the price of the car."

For example, Diaz noted that a car priced at $50,000 might be featured in an ad with discounts and rebates that take the cost down to $30,000. If you aren't eligible for all the incentives, your cost will be higher.

Bait-and-switch on dealer lots

"Don't assume because you can configure a car online, that it actually exists," Diaz said. Your dream car, with the exact options and color you want, might not exist on a dealer lot near you.

"If a dealer doesn’t have what somebody wants, they're going to try to sell what they have on the lot,” Diaz said. "They'll put you behind the wheel of a car to test drive it immediately, whether it's what you want or not."

"Before you know it, you're driving out of there with something that's $200 more a month than you wanted."

If you can be flexible about which car you want, you'll be happier in the end, Diaz said. And if you aren’t in a hurry, you might be able to order your dream car from the factory. He noted that ordering a new car can sometimes save you money.

The all-day dealership visit

Buying a new car is a big financial decision. It’s also an emotional one.

"People spend a lot of time in their cars," Diaz said. "It becomes emotional because it becomes part of our identity."This works against you in the car dealership, and salespeople know it.

"You forget that you can get up and walk away at any moment," he said.

Less scrupulous car salespeople will "lose" the keys to your trade-in. They'll claim they have to get the car you want from an offsite lot. Or they might be detailing the car they want to show you (Diaz said this could be dealer code for fixing a dent or ding).

The longer you stay at the dealership, the more likely you are to get tired and hungry. You just want to go home.

"If they wear you down enough, you'll say yes to everything," Diaz said. That's when you are susceptible to an upsell you might regret later.

"If you want to make a good financial decision, leave your emotions out of it," Diaz said. "Don’t be afraid to walk away and come back later, no matter how much you like the car."