I just noticed coupons.com has a new $3 Similac coupon! This will make the 1 liter of ready-to-feed formula only $0.86 at Walmart! I've heard Target has a similar price as well.
$3.86 Similac ready-to-feed formula, 1 liter
-$3 MFQ HERE
That comes out to $0.027 per fluid ounce! (Regular price of powdered Similac at Walmart is $0.16/fluid ounce.)