The deal with Walgreens is that they print out Register Rewards for special offers they have both weekly and monthly. These Register Rewards are actually "Manufacturer Coupons". This means, when you shop at Walgreens and want to use Register Rewards, you have to purchase an item to apply this rr to.
Example: I am buying a Revlon Mascara, and using a $2/1 Revlon coupon. I can't also use a $2rr because it is a manufacturer coupon and so is the Revlon coupon. So I have to buy another item to apply the rr to. Usually, you're browsing the store looking for "fillers"; i.e. the cheapest thing you can find (and probably don't want or need) so that you can use your rr. Sometimes you get lucky and find $.25 ibuprofen or something, but usually you're buying some random item on clearance for $.50. This kind of sucks.
Well. A poster on Hot Coupon World had a stroke of genius. And I am totally stealing it. You can order pictures online and pick them up and pay for them at Walgreens. Each 4x6 photo costs $.21 (including tax) and if you order a bunch individually, you have $.21 fillers that you do want.
I am currently online uploading and ordering photos for my fillers for this week's deals. Sweet.