Full episodes of "American Horror Story: Coven" are available online at Netflix, Google Play and Playstation Store. It is also possible to download single episodes of "Coven" on the Google Play store and PlayStation Store.
A Netflix subscription is available for $10 monthly, as of 2015. Another option is signing up for a free one-month trial of Netflix on the Get Started page of the site. It would be feasible to watch the season of "American Horror Story: Coven" in one month.
Episodes are available for downloading from both the Google Play and PlayStation stores for $1.99 each. The entire season is for sale from the Google Play store for $19.99, and from the PlayStation store for $19.99 in SD and $29.99 in HD.