The struggling U.S. network carrier T-Mobile is playing its ace to lure in more users by launching HTC One S in the market. The phone is priced at $199 on 2-year contract terms. But iPhone users can get the new device without having to dig into their pockets.

In its co-called "Magenta Deal Days" promotion campaign, T-Mobile is offering $50-$200 discount on HTC One S, if customers trade-in their old iPhone. The discount depends on the condition of phone. The only criteria is that the phone should be functional - no matter how many scratches it has.

"T-Mobile continues to make getting a great 4G smartphone easy with our latest 'Magenta Deal Days' promotion. No matter how old their phone, and even if it's valued less, T-Mobile will offer customers a guaranteed minimum trade-in value," said John Clelland, senior vice president of marketing, T-Mobile USA.

For an iPhone in really pitiful condition, customers have to satisfied with $50 discount only. On the other hand, in return of a flawless iPhone, T-Mobile is offering HTC One S free of cost. The so-called Magenta Deal Days are scheduled to conclude on May 8, starting today (April 25). The trade-in discounts are also applicable on other T-Mobile's 4G LTE-powered smartphones, including Samsung Galaxy S2 LTE and HTC Radar 4G.

In addition, T-Mobile is also including other smartphones in its Magenta Deal Days scheme to trade-in. For Android-, Blackberry- or Windows-powered phones, at least $100 is guaranteed. Even Symbian phones, running OS v9.0 or higher, will fetch you $100. For the rest of phones, $50 is the quoted price.

Trade-ins are available at all T-Mobile stores across U.S. We suggest you to hurry up as the deal is ending on May 8. So, it is the right time to ditch you slow speed phones and get a 4G smartphone today.

Customers can check the guaranteed trade-in value of their device before going to a T-Mobile retail store by clicking here.

(reported by Johnny Wills, edited by Surojit Chatterjee)