In Austria the former provider "one" had a prepaid plan, where you where not billed for listening to your mailbox and talking to the mailbox of others using the same provider. You can imagine that they did not earn much among teenagers.
In Eastern Europe when cellphones became widely popular I remember a plan in which the first 3 seconds were not added to the bill and we as teenagers were making the best use of those seconds. Text messages weren't really a thing back then.
