I watched it free on Amazon Prime, but I guess they can change that!
I just checked and yes, all three seasons are still free via Amazon Prime.
All free shows on Amazon Prime have a banner on the top left corner that says "Prime".
I don't watch Prime as much as Netflix, but it is fair competition for Hulu (but I don't watch too much TV anyway).
If considering a Prime subscription, I also liked "The Expanse", loved "the Tick" as a campy mindless brain-dump superhero show, and currently watching ""The Boys" (series about morally-challenged superheros).