Forum:KB:What is the canon for Communication addresses (in universe e-mail, phone number, etc)

So if I was hanging out in Anchorhead and needed a ride from Luke (Ep IV Luke that is), how would I get a hold of him?

I read that the Galactic Holonet is expensive and rare and not used except for large corporations, the military and the very wealthy.

So what about getting in touch with some common-folk? Do they have a number designation? A intergalactic e-mail address? FaceTime?

What's the canon on this?