I was using Justwatch[0] for a 2017 series and saw I could stream it for free on the Roku Channel[1]. That was a surprise to me, and Roku Channel has some quality stuff, rotating through month by month. In addition, they show some commercials, but with a nice UI feature: a timer in the upper left that shows exactly how long the ads will play. That is a new feature to me. I wish all commercials came with a countdown timer like that.

[0] https://www.justwatch.com/us

[1] https://www.justwatch.com/us/provider/the-roku-channel