One week after AT&T announced that it will soon increase the price of its grandfathered unlimited data plan — the third price hike on that plan to date — T-Mobile has revealed a new deal to tempt those with AT&T’s grandfathered plan to jump ship.

T-Mobile’s WTH (Why the Hike) Deal will launch on June 20th. With this offer, AT&T customers with a grandfathered Data Unlimited for iPhone on 4G LTE with Visual Voicemail plan can get a $250 prepaid card when they switch to T-Mobile.

AT&T customers interested in taking advantage of the WTH Deal can go to a T-Mobile store or call 1-800-T-MOBILE starting June 20th and mention that you’re switching from AT&T and want the WTH Deal. You will need to validate that you’re eligible for this deal before you’ll get your $250 prepaid card. The offer is open to AT&T customers who are on the grandfathered Data Unlimited for iPhone on 4G LTE with Visual Voicemail plan or were on it through June 7th, when AT&T’s latest price hike was announced.

The WTH Deal can also be stacked with T-Mobile’s current offers. This includes Carrier Freedom, which offers up to $650 in the form of trade-in credit and a prepaid card to customers to pay off their contract or phone payments when they sign up for a T-Mobile One plan.

AT&T’s grandfathered unlimited data plan originally cost $30 per month, but starting next month, anyone still clinging to that plan will pay $45 per month to keep it. There are likely some AT&T customers frustrated by this latest price hike, so it’s smart for T-Mobile to offer them $250 to tempt them to make the switch.

Source: T-Mobile