DETROIT - Want to take some of the stress and mystery out of the car-buying process? Get on the Internet.

Auto Web sites - once filled mostly with reviews and advice - are getting more sophisticated, connecting potential buyers with dealers and offering instant price guarantees. Some let buyers estimate their trade-in values and turn in credit applications online. One company even lets buyers complete the entire sale online and get cars delivered to their door.

The Internet lets shoppers enter a showroom armed with the same information as a dealer, said Chantel Lenard, Ford Motor Co.'s U.S. marketing director. Sites let buyers configure their vehicles, see what others paid and estimate the trade-in value of their current car or truck. They could even walk into a dealership with a price locked in.

"It's truly become an equalizer in the shopping and negotiating process," Lenard said at a recent Ford event.

The no-haggle approach can have a downside. In person, a dealer might drop the price even further, or throw in extras like floor mats or a satellite radio subscription. But for many consumers, the convenience is worth it. And the multiple sites that let you check deals can help assure you're getting a fair price.

Auto sites are rapidly adding features and content to attract buyers. For example, an upcoming mobile app from TrueCar.com will let shoppers submit photos and information about their used car to dealers, who will bid to buy it.

Here are some of the best places to shop for cars on the Web:

* Edmunds.com (www.edmunds.com) got its start in 1966 as a paperback car-pricing guide. It won the highest ranking in J.D. Power's 2014 survey of car shopping sites based on content, ease of navigation, appearance and speed. Edmunds lets buyers shop for new and used cars and also offers reviews and advice.

Once buyers choose a car and trim level, they can see the average price paid for that car in their area and get an estimated price from Edmunds. A 2014 Hyundai Sonata SE is estimated at $23,760 in Chicago, for example, or $540 less than Hyundai's suggested retail price. Shoppers who enter their name, e-mail and phone number can get a specific, locked-in price from dealers before heading to the showroom. Dealers pay Edmunds a monthly fee to be part of the network.

J.D. Power also gives high marks to Cars.com, which connects shoppers to dealers who offer a quote; U.S. News Best Cars, which ranks cars and tracks deals; and Kelley Blue Book, which determines a price buyers should expect to pay based on local demand, seasonal trends and other factors. Kelley Blue Book says the 2014 Hyundai Sonata SE should range between $22,845 and $23,602 in Chicago.

* TrueCar (www.truecar.com), which was founded in 2008, monitors millions of transactions to determine the average price of a car in your zip code. For example, the site estimates a 2014 Hyundai Sonata SE will cost $20,392 at a TrueCar certified dealer in the Chicago area. In Atlanta, TrueCar dealers will likely offer the same car for $21,369. Potential buyers get a guaranteed price they can take to a certified dealer. In return, dealers pay TrueCar $299 for every new vehicle sold through the site and $399 for every used vehicle.

TrueCar says nearly 400,000 people bought cars through its 7,700 certified dealers last year.

John Krafcik, TrueCar's president, says it takes around three hours to finalize a car purchase. To ease consumers' frustration, the industry wants to whittle that down to an hour.

- General Motors' Stop-Click-Drive program (http://shopclickdrive.com/) lets buyers shop via local dealer Web sites, estimate the value of a trade-in, estimate monthly payments, turn in a credit application and set up a time to pick up the car at the dealership. The program is good for Chevrolet, Buick, Cadillac and GMC vehicles and was expanded to all 50 states last year. GM says it has sold more than 3,700 new vehicles through the site, which is offered through 40 percent of the company's 4,300 U.S. dealers.

- Carvana (www.carvana.com ) is perhaps the most radical model, allowing buyers to bypass dealers entirely. Shoppers can browse Carvana's used-car inventory, apply for financing through its partners and arrange for pick-up or delivery - all online. Buyers can choose to pick up their car at Carvana's "vending machine," a three-bay garage in Atlanta. They're given a special code to open the door and hop in their car. Carvana will also deliver a car anywhere in the country. A delivery to Chicago, for example, costs $600; delivery in Atlanta or Nashville, home of the company's distribution center, is free. Carvana, founded last year by Phoenix-based DriveTime Automotive Group, owns all of its inventory, so it gives shoppers fewer options than sites that search other dealers' inventories. But Carvana estimates that cutting out dealers saves buyers $1,500 per car. Carvana was offering a 2011 Sonata SE for $15,500 - sorry, no 2014 model available. The company won't give exact sales figures, but says it has sold thousands of cars since its launch last year.