Scrivener is a writing software application aimed at writers of all kinds—novelists, journalists, academics, screenwriters, playwrights—who need to structure a long piece of text while referring to research documents. Scrivener is a ring-binder, a scrapbook, a corkboard, an outliner and text editor all rolled into one.
Cost: $45 (regular); $38.25 (educational discount) from Literature and Latte (price as of 11/07/18). However, there are discounted rates students, educators, and scholars. Scrivener also available for purchase elsewhere (e.g. Mac App Store).
Trial: 30 day trial of actual use. This means if you only use it two hours a week, you can have the trial for 15 weeks.
Both Mac and Window versions are available.
NOTE: Scrivener 3.0 is now available for macOS and is coming for Windows. If you have an older version of Scrivener, you can update to Scrivener 3.0 for $25. (11/07/18)
Unfortunately, Scrivener and Zotero don't work that well together. Here are some videos with suggestions as workarounds:
How to use Zotero with Scrivener (video, David Gee, May, 2018) - comments suggest works but technical