EDIT: Today's Once-in-a-lifetime sale actually has them cheaper - price and expiry updated.
Best option would be to click and collect. Ends today.
The "Lithium Coin" 3.0 volt Energizer ECR2032 is designed to have a long shelf life and provide continuous energy under most temperatures. Extremely durable, it has found favour in compact devices that require the exact properties exhibited by the CR2032 cells – durability and longevity.
Very cheap compared to other places:
That's actually reasonably cheap for quality ones. I've bought some at 10c each and most were duds… just like most of my girlfriends, ZING!