There’s good news and bad news for AT&T subscribers, as the carrier introduces some new promotional data plans on August 15.

If you’re on a plan with 10GB of shared data, the same $100 per month you’re paying now will get you 15GB of data under the new plan. And if you’re paying $150 per month for 20GB of shared data, that same plan will be $10 per month cheaper.

AT&T’s lower data tiers aren’t getting quite the same treatment. The carrier is eliminating several of its price tiers, and replacing them with slightly more expensive plans with more data. For instance, AT&T’s $25 per month, 1GB plan will no longer be available for new subscribers, but a new $30 per month plan will offer 2GB of data instead. See the following chart for a full rundown:

Those monthly per-line fees only apply with AT&T Next, in which you pay the phone’s full price in monthly installments. Unlike rival Verizon, AT&T isn’t getting rid of the two-year contract with subsidized phone pricing, though the monthly access charge jumps to $40 per month for on-contract plans.

To be clear, existing subscribers won’t have to change their plans, so you can stick with the data tier you’re on if it works for you. Likewise, subscribers will have to visit an AT&T store, call, or go to AT&T’s website to sign up for the new plans. AT&T says these are promotional rates, but there’s no indication of how long they’ll last.

Why this matters: Aside from being a good deal for a certain segment of AT&T subscribers, the plans show just how desperate carriers are to stay ahead of one another. But instead of just slashing prices, carriers are now focused on giving away more data. T-Mobile, for instance, is offering four lines, each with 10GB of data, for $120 per month total through Labor Day . It’s unclear how sustainable these promotions are, but customers should enjoy the competition while it lasts.