I want publish one free applicataion and with some features in lock mode after pay unlock the features iphone app?

How can i enable some features in lock and some features in unlock mode in my iPhone application.

Like some are enabled for user in a free mode and some are enabled after payment.

Thank you.

Google has all the answers (example)

You could use a .plist file where you store which features are available and which are locked. When a user then unlocks a feature through In-App purchase, you just update the file so that the new feature is available.

When your App starts, read in the file and use if statements to check if the requested feature is available for the user.