2-Pack Duracell Coppertop Alkaline N 1.5V Medical Battery $0.92 at Amazon
Amazon has the 2-Pack Duracell Coppertop Alkaline N 1.5V Medical Battery for $0.97 - 5% off with Subscribe & Save (can cancel at any time) =
$0.92 with free shipping on $25 or with Prime.
Walmart has it for the same price (no pickup).
Equivalent to LR1, E90, MN9100 and 910A.
Original Source of Info