Car-buying websites have long offered consumers fodder for haggling. But now buyers like Clayton Whisler can tap the latest auto intelligence from anywhere including the dealer's showroom. While recently negotiating over a new ride, the Orange County, Calif., IT manager called up an app on his smartphone, typed in his desired vehicle and flashed the screen at the salesman. The result? A price drop of $1,500.

These days consumers can use some help unstacking the dealer deck: New-car prices rose 5 percent last year, according to Edmunds.com, and rebates and financing have become less generous. So when the sales guy lowballs your trade-in, Kelley Blue Book's app offers an objective source for fair value. Cars.com's mobile program lets you compare prices at local dealers. And ILeaseMyCar Pro helps consumers calculate financing variables. Review apps, like DealerRater and Yelp, can also provide useful feedback, but relying on novices has its perils: One recent poster crowed about a $6,000 price gap on a Mercedes E350 at two Los Angeles dealerships not realizing that was the standard spread between a sedan and a convertible.

GMC Acadia

New mobile apps can provide the price consumers are actually paying for a new or used car. One buyer recently used an app to shave more than $1,500 from a crossover's $34,000 asking price.