The local QFC (super market) sells Campbell's cream of chicken and cream of mushroom soup for $1.49 a can. Right now its on sale for $1.00. If you buy 10 they knock $5.00 off, making the final cost of each can $0.49.
So, let's say you decide to buy 800 cans of soup. (hypothetically of course!) The original cost would be $1192. The sale price would be $392, making your savings $800. Your receipt will be literally 12 feet long and it will take the cash register 17 minutes to process an 800 can sale.
Also, people in the store will look at you with wonder, they will ask you why you're buying so much and they will also discuss it with their line-mates who they don't even know.