T-Mobile is upping the stakes when it comes to ensnaring iPhone customers. 

Now the "un-carrier" is offering its iPhone 5 at $0 down to any customer willing to trade their current iPhone 4 or iPhone 4S model. They'll receive a credit of up to $120, which can be put toward paying off paying off the phone (monthly payments), a T-Mobile bill,  or purchasing accessories or another device. 

The offer lasts through Father's Day on June 16. 

[via Boy Genius Report]