Buy Bookends for iOS
Bookends for iOS without a Standard Version in-app purchase is limited in the following ways: searches return a maximum of 20 references, only 50 references can be stored in your local database, PDFs that you annotate on the iOS device are watermarked, and ads are shown. To have full access without these restrictions you must make a purchase from within the app ("in-app purchase”).
Pro Features Yearly Subscription (cloud sync of references and attachments, multi-library support, unlimited barcode scans) is a separate in-app purchase ($9.99) and requires a susbcription that is renewable on a yearly basis.
Subscription is for one year and can be auto-renewable. The subscription can be managed in iOS → Settings → iTunes & App Store → Subscriptions. The subscription might renew if it wasn't canceled more than 24 hours before the renewal date.
If the subscription is not renewed, Pro Features will be disabled.
No cancellation of the current subscription is allowed during the active subscription period.
Standard Version - $9.99
Pro Features Yearly Subscription - $9.99