Autodesk SketchBook is now completely free. Up until this month, certain features—the majority of the app's brush presets, for example—were only available as part of a subscription plan that cost $4.99 a month or $29.99 a year. The full feature set does still require an Autodesk account, but that's also free.
SketchBook's features previously known as Pro Tools, including more brushes, customizable canvas sizes, and higher-quality image imports, are now available to all users. Prior to this change, a paid subscription made all those tools available on all platforms (in addition to Android, there are versions of the software for Windows, Mac, and iOS).
Autodesk isn't issuing refunds for users who purchased an annual subscription, but monthly subscriptions have been canceled, and plans won't auto-renew. Following a seven-day trial period, you'll have to sign up for a free Autodesk account to continue using the platform.
There's still an Enterprise license of SketchBook available to purchase on Autodesk's website for $10 per month or $85 per year—but the features of the software are the same as the normal version.