I am far too impatient to make several trips to my car when unpacking groceries, so I end up hauling everything at once. This painful problem is exactly what the Yoke Shopper was designed for.
The Yoke Shopper secures several shopping bags and allows users to sling them over or across their shoulders. Obviously, this frees up your hands and prevents the handles from digging into your skin. Although, if you are a big eater you will probably have to strap a few of these things on—which will just end up transferring the pain from your hands to your shoulders and lower back. [Yoke Shopper via Red Ferret]