(CNN) -- You can keep them for only a week. But T-Mobile is handing out free iPhones, along with a trial run of its cellular service, in the latest in a string of unorthodox promotions for the No. 4 wireless carrier in the United States. Through "T-Mobile Test Drive," curious consumers will get an iPhone 5S loaner and seven days of unlimited data to check out the service. Starting Monday, people can sign up for the program online. If they're not impressed, they can drop the phone off at any T-Mobile store, at no charge. People must give T-Mobile a valid credit card number to get a phone. If they return a cracked or water-damaged phone, they're billed $100. If they don't return the phone at all, they're billed $700, plus tax.
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"T-Mobile Test Drive" program gives the curious an iPhone 5S for seven days
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The week comes with unlimited data on the network
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It's the latest in a string of unconventional tactics by the No. 4 carrier
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Promotions come as Sprint is reportedly trying to buy T-Mobile
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