Playing for free is completely possible. This isn't a pay to win game, especially now that there are daily blessings.
I have friends who have never spent a penny on the game, and capped 3 times including 77. Granted, the free offer option is disabled at the moment, but I don't expect that to be permanent.
Now, of course spending money makes the game easier, and has its benefits, but it's not a neccesasity.