Well I went through the Microsoft Store at Amazon and got it for 50.19 - whilst there were quite a few negative reviews mostly they were mac users, people who didn't like changes from earlier Office versions or people who were having problems installing the software. After buying it took me directly to the Office site and was all set up quickly - probably helps that I already use an MS account.
To be honest, Office for Mac sucks by comparison to the Windows version.
It always seems to lag in terms of features, and has some weird esoteric ways of doing things in such as Excel that are just subtly different enough to the Windows version to cause confusion and irritation.
Having said that, I am coming at that from the Office 2011 (Mac had 2011...go figure) version and only touched on the next (2015?) version which did seem somewhat better but still not great.
Good buy, by the way.