I am very new to android.. I am working on In App billing.. My question is what is the main purpose of Managed and Unmanaged state while adding the In App product..
As of Version 3 of Google's IAP Billing API this has changed. Both consumable (multiple purchase) and non-consumable items are "managed". Tf you want to use Version 3 of their API, all purchases must be created as "managed". You can then decide if the item should be consumed later.
Here's a link to their docs: http://developer.android.com/google/play/billing/api.html#consumetypes