Here are you getting your information? Office 365 (2019) if subscribed to Home version is either $9.99 month to month or $99.00 for a year at a time. Now that is for Home users (or possibly small Business). I don't know the price of the permanent license
version.
Microsoft also has Business oriented Subscriptions and Permanent License versions. You will have to go to Microsoft and look in Business software section find out Prices.
The advantage to the subscription model is that the latest updates, and feature, and bug fixes are addressed at least monthly and usually once weekly. The only advantage to permanent license version is that you don't have to pay a monthly or yearly fee.
The disadvantage is that only bug fixes are addressed and new features are grouped together when a new permanent licensed version comes out, in two to three years.
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