This week you should be able to pick up a box of 20 Extra Strength Excedrin for free from Target! Please note that Target prices vary from store to store but even if it isn't free for you it shouldn't cost much at all.
* Buy a box of Extra Strength Excedrin(20ct) - $3.59
Use the $1 off printable coupon found here plus the $3 off Target printable coupon found here.
Final cost should be $0!
Target store coupons can be combined with manufacturer coupons for the same product per their coupon policy. View a copy of it here.