Charmin Ultra, $19.11 (with S&S plus $0.25 coupon on product page for me)
Charmin Ultra Soft, Double Rolls, 4 Count Packs (Pack of 10) 40 Total Rolls
(equivalent to 80 regular rolls)
19.11/ 80 regular rolls (40 doubles *2) = $0.238 / roll. This is cheaper by
a cent or so from the last deal.
Link: http://www.amazon.com/gp/product/B003WJ85DA/