I am guessing Office 10 was released around 2010. So, after 10 years, they are not going to support it. 

Currently, they do offer Office 2019.  Best Buy has MS Home and Office 2019 for around $150. I expect that is the price you will find most areas.  This will be a product you buy and download - not an annual fee product ( which is what the Office 360 product is).

As others mentioned, you can find other products, such as the Apache, Libre, Open Office products that were mentioned.   If you don't share documents back and forth, these work fine.  If you share documents back and forth with others, and they are using MS Office/Word, you may find formatting quirks that will drive you crazy.  This is the main reason that I continue to use MS Office.