cost of microsoft 365

https://www.microsoft.com/en-us/microsoft-365/compare-all-microsoft-365-products?activetab=tab%3aprimaryr1

The $100 per year option allows you to install Office 365 on up to 6 devices of any kind you own, whether it's Windows, Mac, iOS or Android. The $70 per year option is a single license for one device.

A good question to ask Microsoft, since it is their product.

Look into the Free LibreOffice, it handles MS Office files…

https://www.libreoffice.org/