So today, after running out of canned food, I went to Walgreens and used the coupon for $.50 off 18 cans of cat food. At the check-out, they gave me a coupon for - wait for it - $.50 off 30 cans of cat food.
At that point the savings isn't all that much. I have another 18-can coupon floating around, I think - I wonder if using it will produce another 30-can coupon? Plus it seems like there is some kind of progression there, but I'm not math-savvy enough to figure it out without more headache than I'm willing to spend.
8 cans generates a 12 can coupon
12 cans generates an 18 can coupon
18 cans generates a 30 can coupon
8+4 =12, and 12+6 =18, but it takes 12 more cans to = 30 instead of the 9 I would have expected if it was the first logical progression that occurs to me. If it has something to do with square roots or such it's beyond what I can do in my head. Do I at least get some points for noticing the n+n/2ness of the first two transactions? I'm such a wannabe...