Today (August 3) until 11:59 pm CST, Best Buy is offering the Google Nexus S smartphone for free.

According to the press release, customers can receive the Nexus S phone free as a new phone or an upgrade purchase at all Best Buy, Best Buy Mobile specialty stores, and online at BestBuy.com/Mobile.

The catch is that customers must sign a two-year contract with AT&T, Sprint or T-Mobile.

Each carrier has different contract requirements. AT&T requires a minimum data service of at least $15 per month and early termination fees have a starting penalty price of $325, while Sprint requires a $10 monthly access plan with a $200 early termination fee.

The Nexus S comes with the same operating system as Android 2.3 (Gingerbread), a touch-screen display that measures 4-inches, 3G/4G storage, and last but not least a 5.0 MP digital camera that features autofocus and flash.

The Nexus S, without contract, normally costs $529.99 on AT&T and T-Mobile, while the 4G version Sprint normally costs $699.99. With the purchase of a new two year contract, Best Buy has been selling them for $99 on AT&T and T-Mobile, and it’s been free with a Sprint contract.

Google may be releasing a new Nexus phone soon (Nexus Prime) and Apple’s iPhone 5 will likely be released in September.

The tech blog Boy Genius Report suggests that customers may not want to commit to a two-year contract with high penalty fees – considering that new smartphones are on the horizon. Boy Genius Report warns shoppers to thoroughly consider the offer before committing.