RICHMOND, Va. — CarMax is looking to boost sales prospects in 140-character, tweet-size chunks by launching a new promotion using the social networking Web site Twitter.

Company officials are planning to give one consumer $25,000 toward the purchase of a used vehicle from their nationwide inventory. The award is the grand prize in the promotion CarMax has dubbed "Tweet Yourself to a New Ride."

CarMax is directing consumers to its Web site to find to find the specific phrase to tweet on Twitter. The action automatically enters the user into the contest.

Executives plan to run the promotion for eight weeks, climaxing with the grand prize giveaway. Along the way, CarMax will give out eight gas cards valued at $250 to contest entrants selected at random.

A full list of rules and regulations, as well as frequently asked questions, can be found on the contest page, www.carmax.com/tweet.

Company officials pointed out that they already use Twitter messages to share information about vehicle details and other industry news. They wanted to extend that reach with this promotion.

"Giving away a late-model, fully reconditioned CarMax vehicle is an excellent way to draw attention to both our great cars and our efforts on Twitter," explained Joe Kunkel, senior vice president of marketing and strategy.

"This Twitter contest is a fun way to promote our brand and to share our story with car shoppers who haven't previously heard about us," Kunkel concluded.