You can score a free Rimmel London Mascara or Eyeshadow at Target (or get one free and the second cheap) by stacking a Target coupon with a manufacturer coupon.
print the Target Coupon for $2 off Rimmel +
The Facebook coupon for $2 off
You may even have some possible overage. There is also a $1 off coupon here if you need it. Note that you can only print the Target coupon once, but the Facebook coupon you can print twice by hitting the back button after the first coupon has printed. Make sure your printer is completely on and ready to print before you hit print.