Yes, this is a decidedly low-tech product and not designed specifically for iOS devices, but Ziploc bags provide terrific protection against dust, and they help keep your device dry in a downpour or a capsizing boat.
Plus, they're disposable and extremely inexpensive to replace, and they come in multiple sizes to handle all of your iOS devices.
If you're on a strict budget but still want to protect your valuable iPhone, iPad, or iPod touch, sealing it in a Ziploc bag is a smart strategy.
Ziploc Freezer Bags for iphone
Source : iPhone Life Magazine 2012