With all of the bundles and sales going on, it's not difficult to get a subscription to Disney's new streaming service at a discount. If you're buying a new Chromebook for Black Friday, or some other time over the next two months, you'll get three free months of Disney+ included.
A new page on the official Chromebook site reads, "Incredible stories meet the power of Chromebook. New subscribers get 3 months of Disney+ when they activate a new Chromebook between 11/25/2019 and 1/31/2020." The offer is only valid in the United States, even though Disney+ is live in a few other countries as well.
The small print at the bottom of the page outlines the process. You'll have to set up the Chromebook, visit the offers page (which usually pops up after setup anyway), get your discount code, download Disney+ from the Play Store, and enter the code when you set up an account. Additionally, your payment method will be automatically charged after the trial period expires, so make sure to set a reminder to cancel it (if desired) after the free period is over.
If you're having trouble redeeming this offer, Google has a support doc to help you.