T-Mobile’s free line offer is giving some customers a very expensive surprise

In an attempt to calm the storm, T-Mobile rolled out a new free line promo for eligible users. However, it turned out to be not entirely free – there is a one-time $10 “Device Connection” fee, which isn’t terrible.
But now, some users are saying there is more to it. One person shared online that they were hit with a $117.50 charge for the supposedly free line. Another chimed in with a similar experience. While it might just be a billing glitch, there is a chance T-Mobile‘s policy includes a one-time charge for certain users that gets credited back in the next billing cycle.
Anyone else getting charged for the new ‘free’ line? Got a $117.50 charge on it.
– JuanG12, Reddit, April 2025
The user’s bill reportedly came with a huge charge for the new free line. | Image credit – JuanG12/Reddit
Just contacted them and they said I’d have to pay it this cycle and they’d credit me the next cycle. They didn’t tell me that when I added the line. They said my (at the time) plan and bill would remain the same. I just had to pay the activation fee.
– JuanG12, Reddit, April 2025
They told me that the first bill cycle might have a charge, but it will be reversed on the second bill.
– TealCatto, Reddit, April 2025
So yeah, don’t be too shocked if your next bill looks higher after adding that free line. It is definitely frustrating – especially if the charge is steep – but thankfully, it doesn’t seem to be a widespread issue. And actually it might just be that the free line got added to the wrong plan, which T-Force should be able to fix.
It is always smart to read the fine print before jumping into these promos, just to avoid that “wait, what?” moment later. For example, one T-Mobile user recently said they double-checked with two different reps to confirm they qualified for the free line, only to find it wasn’t free when the bill came. After a third call, they were suddenly told they didn’t qualify after all.
Billing slip-ups aren’t just a T-Mobile thing, though. Carriers mess up more often than you would think. One Verizon customer, for example, had so many billing issues, the FCC probably knows them by name. Another customer got hit with a $700 bill despite never being a Verizon customer. And not long ago, an AT&T customer’s promised discounts disappeared, leaving them stuck with an unaffordable bill.