The best texting app in the iOS App Store is (for the moment) free.
I’m a big fan (and daily user) of Launch Center Pro, which is created by the same developers who make Group Text+.
Group Text+ makes sending texts to a pre-saved group (or individuals) really easy and fast… and it even comes with a bunch of hilarious gifs you can send! (I’ve gotten way more into this last feature than a man my age probably should….)
Check out the app here–free, for the time being.