Today, a mail from apple had reached my iPhone to inform me that the official apple’s bumper will be for free for iPhone 4 user. Those who had bought their iPhone 4 before July 23 should apply for their free bumper before august 22th.
To apply, simply download an application from app. Store named “iPhone 4 case application program” and fill in the required information.
Those who had bought their own official bumper from apple can get their cash back from apple.