If you are current Carleton faculty or staff, but plan to leave Carleton soon, you can purchase a rough equivalent of the previous option, for you to use with a personal, non-Carleton, email address, for as long as you renew the annual license. This is what Microsoft calls their "home use program." But this only works for faculty and staff, and only if you initiate the process while your CarlNetID@carleton.edu email address still works.
To get started, in any Web browser open microsoft.com/home-use-program and enter your CarlNetID@carleton.edu email address. A while later, check your Carleton email for a new message from Microsoft that may look like the following, with a subject like, "Check out this special discount, just for you" (sounds like spam, doesn't it?).
The Web browser link under the blue button really is customized just for you (hence your name in the message), and must not be shared. It will take you to a Microsoft login page, where there is one tricky step: Now you must login with a personal, non-Carleton, email address, which will be your Microsoft account.
This will take you to a Web page that shows you save 30% on an annual subscription to either Office 365 Home ($99.99) or Office 365 Personal ($69.99). This discount applies forever, as long as you renew the subscription annually. The Web page compares the two subscriptions in detail, but Office 365 Home will be the best choice for almost everyone. (Please ignore the section of the page titled, "Other Office Products"; those do not apply.)
To learn more, see the Frequently Asked Questions page and the instructions on how to install or reinstall Office 365 purchased through this Home Use Program (HUP). Carleton does not administer these purchased subscriptions, so all your interactions will be directly with Microsoft.