Rather than paying a hefty up-front price, you pay a monthly or yearly fee and get access to the latest version of Office for as long as you pay the fee. Office 365, on the other hand, is the new way Microsoft wants you to buy Office. You pay once to buy a version of Office 2016 you can install on a single PC or Mac and use for as long as you like. Here’s the main difference: Office 2016 is the the traditional Microsoft Office product, sold for a one-time, up-front fee.