Get ready for your home Internet to feel like your smartphone — bound by data caps, a large overage fee waiting to happen.

Comcast gave some users the bad news Thursday — not surprisingly, before a long weekend. Consumers who exceed 300 GB in a month will have to pay for overages at $10 per 50 GB tier.

Not surprisingly, they have the option to pay an extra $30 to get the service they have currently, without caps.

Internet service providers like Comcast have been champing at the bit to change their business model and charge consumers by the bit the way wireless providers do. Comcast’s initial allowance seems generous — some notes sent to users say it’s unlikely they will hit the cap based on their prior usage — but it’s easy to imagine that’s temporary. The Internet keeps birthing high-bandwidth applications like streaming HD video. Users will ultimately run into these caps. And there’s nothing to prevent Comcast from lowering the limit going forward.

“An important update about your XFINITY Internet service,” the email reads. “We’re writing to let you know that we will be trialing a new XFINITY Internet data plan in your area. Starting October 1, 2015, your monthly data plan will include 300 GB. We will also trial a new “Unlimited Data” option that will give you the choice to purchase unlimited data for $30 per month in addition to your monthly Internet service fee.”

The news comes with some “courtesy” concessions from Comcast.

“We’re … implementing a three-month courtesy program. That means you will not be billed for the first three times you exceed the 300 GB included in the monthly data plan,” the email says. “If you are on the 300 GB plan, we will send you a courtesy “in-browser” notice and an email letting you know when you reach 90%, 100%, 110%, and 125% of your monthly data usage plan amount.”

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Mail-in voting: Is it really safe? All you ever wanted to know, FAQ style If you haven’t seen one of these emails, you can learn more about the data usage trials at Comcast’s website.

On its frequently asked questions page about the new usage fee, Comcast describes it as a trial, and says it impacts consumers in the following areas: Huntsville and Mobile, Alabama; Tucson, Arizona; Fort Lauderdale, the Keys and Miami, Florida; Atlanta, Augusta and Savannah, Georgia; Central Kentucky; Maine; Jackson and Tupelo, Mississippi; Knoxville, Memphis and Nashville, Tennessee; and Charleston, South Carolina.