From now through December 26, 2009, you can get free batteries at Staples! Just sign up for their Rewards card and then buy a 20-pack of Duracell batteries at $12.99 and you'll get $12.99 back in Staples Rewards. Remember Staples Rewards are store credit.

This deal can be done twice per week per customer. Great for all of those toys that require batteries!
More details here.