16 Duracell Rechargeable AA NiMH Batteries, (2 8-Count Packages) on Amazon
for $15.30 (S&S, AC).
Link: http://www.amazon.com/Duracell-Rechargeable-Batteries-8-Count-P
Select Subscribe and Save (drops price to $16.50)
There is a $1.50 coupon on the page.
Total (if you have Prime shipping): 13.50