I don't know about the rest of the world but in the UK text messages used to cost 10p for each one you send. Multimedia messages were like 40p. Really expensive. WhatsApp came about and made both of these free. The rest is history.
Ironically, SMS are generally free these days but nobody obviously uses them. My SMS app is just full of OTP codes being sent to me.
You're from Brazil? I just want to say, if English is not your native language you'd have a hard time convincing me it isn't.
SMS is the same in the UK these days. Free. MMS isn't though. They still like to scam the older users who know no better.