Associate
I got my Office 2019 in the beginning of the year with a huge discount. I just went to official Microsoft link mentioned already here and checked their list of official retailers. Then I got to each one of them and found the local shop that was the cheapest here. Unfortunately a year after I don't remember the name, otherwise I would have shared it with you straight away. But you can do the same, and who knows, maybe you'll get a better deal.