Here is a five pack from Amazon, for $2.58 and free shipping.
http://www.amazon.com/Maxell-CR2032-lithium-batteries-pack/dp/B006GDL0FY
Walmart has a Panasonic 20 pack for $8.62, free in store pickup.
http://www.walmart.com/ip/UPG-85967-C3986-UPG-CR2032-Lithium-Batteries/21632074