There's a February EasySaver Rebate for $1 on three boxes Kleenex and the 120-count boxes are on sale this week for .89 with the 7-day coupon. There is also a recent coupon for .50/3. Here's the math:
.89 (7-day cpn price)
-.50 (manufacturer's coupon)
Total per box: .39
Edit: The 120-count is not listed in the EasySaver booklet as applicable for the rebate, but it is listed on the Walgreens website. YMMV, but they should honor what their site says.