My first boyfriend was born in the late 70s (UK) and hos family didn’t own a phone — not one landline phone between them — because phones were too expensive.

I was early 80s, and watched landline and mobile costs fall to negligible levels.

My current girlfriend was born in the late 80s (USA, but world traveler with family work), and I think from the start of highschool onward pretty much always assumed there was an internet connection and too-cheap-to-care calls even before everyone made their own VOIP/video chat messengers.