That's what WhatsApp did (except that the trial lasted at least one year, and practically often much longer), and it worked wonders for them.
Even better: Offer a full-featured trial, allow incoming messages for free forever, charge the €4 only for outgoing messages after that :)
That's what WhatsApp did (except that the trial lasted at least one year, and practically often much longer), and it worked wonders for them.
Even better: Offer a full-featured trial, allow incoming messages for free forever, charge the €4 only for outgoing messages after that :)