I think my first questions to you would be:  why do you want Office? How do you use it?

Here is a link to Microsoft Office products, sold on the Best Buy website.  Scroll down the page to see a comparison chart.  It appears to me - and has been my understanding - is that Office 365 products are subscription-based - you will pay an annual fee to use them. 

Microsoft sells a one-time purchase products. This is what other posters are suggesting you look at.  They are MicroSoft Office Home and Student 2021, or MicroSoft Office Home and Business 2021.  From what I see the difference between the two is the Home and Business adds in the Outlook program.  Personally, I use the Home and Student version. IF you go this route, you will need to buy 2 of them - one for each computer.

Alternatives to MicroSoft Office are:  FreeOffice and LibreOffice.   If you don't absolutely need MicroSoft Office, I suggest you download and try out one of these alternatives before you purchase MicroSoft Office.  I personally use some spreadsheets that have macros in them. And these particular macros don't work well with FreeOffice or LibreOffice.  So, I am boxed in to using MicroSoft Office. However, you may not be in that situation. If you are doing basic wordprocessing or spreadsheet work, these options may work well for you. They are worth looking into.  Here is a website I found which compares the two.  FreeOffice vs LibreOffice ... which to try?  I don't know the answer to that. I'd pick one and try it out. See if it works for you. If it doesn't, the worst you have to do is to delete it and try something else.  My 2 cents.

edit: for those looking for Microsoft Office alternatives, here are two more articles worth reading:

Best Microsoft office alternatives

Best Free Office Suites

As you can see, there are lots of options available.