Comment by kelnos

That's exactly how they work, actually. Or at least worked, traditionally. There are assuredly some two-way pagers out there now.

But yeah, you'd usually pay for service in a certain (large) geographic area, and if you wanted to take your pager out of that area while on a trip, or if you moved, you'd have to let the pager company know so they could start broadcasting in the new area.