While it is common to refer to "the Microsoft Office suite" as a singular entity, Microsoft does not include every program in every version of Microsoft Office. Every Microsoft Office suite offers Word, Excel, PowerPoint and OneNote, but the suites contain different features and programs for home and business users, people who need access only on the Internet and those who need offline access, and for different payment options.
The Office Home and Student 2013 suite and Office Online include Word, Excel, PowerPoint and OneNote, while the Office Home and Business 2013 suite includes all of those programs plus Outlook. The Office Professional Plus 2013 and Office 365 suites include everything in the Office Home and Business suite plus Publisher and Access.
Access and Publisher are not available to Office 365 users of the Mac OS. Unlike all the other suites, Office Online programs can only be used while you are connected to the Internet.
Office 365 offers a monthly subscription plan with a varied price depending on how many devices you use with the plan. Office Online is free to use. All other Microsoft Office suites are sold at a fixed cost.