You can buy flex head ratchets at Walmart, Autozone, Sears etc. It may not look exactly like the one pictured in your link. With most the swivel or flex is part of the handle right below the head. Don't know that I've seen one exactly like the one pictured in your link at the above places but the ones they do have should suit your purpose.
Here is a Craftsman similiar to the Snapon, $20 instead of $90 something.