A-Meow-Zing Savings
A few years ago, there was a promotional sample of catfood. The bag cost 3 dollars and it had a 3 dollar coupon inside it. The coupon did not have a weight limit on it.
So I bought a big plastic bin, put it in my trunk, and for an hour, went in and out of the store filling that plastic bin, one $3 bag of cat food at a time, cashing in the 3 dollar coupon the previous bag gave me.
Story credit: Reddit / avec_aspartame