The logic behind many phone plans is that people will pay more if it means lots of features such as high-speed data over 5G, mobile hotspot connectivity, international calling and 4K video streaming. AT&T is a prime example: It recently rolled out a new Elite 2.0 plan, which adds even more perks and starts at $110 a month.

But not everyone needs all those extras, and with costs of nearly everything rising, many customers don't want to pay premium prices. That's why AT&T today introduced Build-A-Plan, an option on the opposite end of the plan spectrum.

Available May 27, the new wireless plan is intentionally basic. For $15 a month (plus taxes and fees), you get unlimited talk and texting and 1GB of high-speed data (which could slow when the network is congested). That's it.

If the base plan is too bare for your needs, you can upgrade to either 5GB of data for an extra $5 a month or 15GB for $10 a month on top of the base price. And if you realize that having unlimited data is more in your comfort zone, you can swap out the limited-gigabyte options to unlimited with SD-quality video for an extra $20 a month, or unlimited with 4K video for $35 a month.

Using your phone as a wireless hotspot is not included, but that feature can be added as an optional extra: Add $5 for 5GB, $15 for 25GB or $20 for 50GB of data.

Fully built-out, the Build-A-Plan would cost $70 a month for unlimited data with 4K-quality video streaming and 50GB of data. That's comparable to AT&T's Extra 2.0 plan that guarantees 100GB of high-speed data, has the same 50GB of hotspot data and delivers SD-quality video. 

Build-A-Plan has no international calling options, no included streaming services and no smartwatch or tablet add-ons. It does come with the standard version of AT&T's ActiveArmor service for blocking spam calls and safeguarding data.

At launch, the plan is available only as a single line and only to new subscribers who bring their own unlocked, eSIM-capable phone. Customers can either port an existing number or get a new one. An AT&T spokesperson said the company will evaluate options for expanding access to other customers in the future.

Build-A-Plan isn't a prepaid plan; it's a subscription service that customers can cancel at any time with no commitment.