AT&T T, -0.48% is willing to pay T-Mobile TMUS, -1.06% customers $450 to switch carriers. It’s clearly a tempting offer, but analysts say T-Mobile users could end up paying a lot more in the long run.

Bloomberg

Starting Friday, AT&T said it would offer up to $250 toward a mobile phone upgrade and $200 in credit per line when T-Mobile customers transfer their service to AT&T, choose an AT&T Next plan and buy a phone at full retail price or activate a phone they already own. (AT&T’s Next plan allows consumers to get a new device every year with an installment plan over 20 months.) The move is a pre-emptive strike against T-Mobile, which is widely expected to come out with a similar offer, says technology analyst Jeff Kagan. “This is beginning to look like a real knock-down, drag-out boxing match,” he says. “This battle between T-Mobile and AT&T is just getting interesting.”