Just a month after officially unveiling its Xfinity Mobile service, Comcast this week opened enrollment for its Xfinity Internet customers.

The debut data options include an unlimited option as well as a per-gigabyte plan. Through the end of July, Comcast is offering the unlimited plan for $45 – that includes unlimited talk text and data, though speeds will be capped at 1.5 Mbps for downloads and 750 Kbps for uploads after 20 GB of usage in a billing cycle. While the plan’s monthly cost will jump to a rate of $65 per month once the promotional period ends, customers who sign up for the $45 rate will get to keep it for two years as long as they maintain the account in good standing and keep their Xfinity Internet subscription.

For those seeking a bit less than unlimited data, Comcast is offering data “By the Gig” at a rate of $12 per GB. This data is sharable across all lines on a customer’s account, and customers will be able to keep tabs on their data usage via the Xfinity Mobile app. The app can also send usage notifications to customers to help them stay on budget, Comcast indicated.

While customers must have an Xfinity Internet account to sign up for the wireless service, those who want to cancel their Comcast internet service down the line will have the option to keep the wireless service – albeit with a few extra fees. Both the “By the Gig” and unlimited customers would have a $10 per line per month access fee added to their accounts. But even the higher cost of unlimited on Xfinity Mobile would figure out to be cheaper than the $80 per month unlimited plan offered by Verizon – the carrier offering backup LTE coverage for Xfinity Mobile’s hybrid WiFi/cellular service.

Those who do decide to take up the Xfinity Mobile offer will have to pick up a new phone. Comcast hasn’t established a bring your own device (BYOD) option, and is instead offering a lineup of newer flagship smartphones, including Samsung’s Galaxy S7 and S8 and Apple’s iPhone 6s, 7, and SE.

The consumer launch of Comcast’s mobile service comes just about a week after Comcast and Charter announced the formation of a wireless partnership in which the companies agreed to work “only together with respect to national mobile network operators, through potential commercial arrangements, including MVNOs and other material transactions in the wireless industry, for a period of one year.” The pair said the deal will help the companies capitalize on “operational efficiencies” by working together on common operating platforms, technical standards development and harmonization, device logistics, and emerging wireless technologies.

Execs at Verizon, which is providing MVNO network services for both companies, said they welcomed the deal.

“They had the right to work together as an MVNO and frankly we encouraged them to work together because dealing with one customer is a lot better than dealing with multiple customers,” Verizon CEO Lowell McAdam commented at an investor conference.