"[Batteries] are marked up as much as 60 percent. Stay away from batteries at the grocery store and instead throw them in your online cart next time you're browsing Target or Walmart's website. Better yet, hop on over to a warehouse store like Sam's Club or Costco where you can find double the quantity of batteries for the same cost as your local supermarket. Since batteries have no expiration date, buying in large quantities is A-OK!"
Source: Flickr User Matthias Rhomberg