Bhphotovideo offers Lowepro DryZone 200 Backpack (Yellow) for $129.99 (reg $229.99) with free shipping.

Product Description:
The Lowepro DryZone 200 Backpack (Yellow) is a totally waterproof, soft-sided 600 denier TXP and 2000 denier ballistic nylon camera backpack. The inner DryPod with patented, waterproof TIZIP zipper provides 100% watertight protection. It's like a dry suit for your equipment. When less protection is needed, leave the TIZIP open and fasten just the inner zipper and top clip for easier access.
The DryZone 200 has a heavy-duty, padded camera compartment inside that is fully customizable. The outer shell comes complete with a technical backpack harness that includes an ergonomic lumbar support and fully adjustable CollarCut shoulder straps. There is a tuck-away tripod holder; self-draining mesh pockets; drain hole; rubber handle; and attachment loops for SlipLock accessories.