So, Google has gone all sorts of crazy with their SMS apps, now killing it in Hangouts without a good replacement (looking at your broken ass, Allo).
I'm still using Signal as my SMS client, and very happy with it, but back through the mists of time, I remember when a text cost a dime apiece, there was another service that came about that let you do almost the same thing, using data.
In fact I still use them if my cell service or wifi goes out; Twitter.
Wow. I'm ancient!