Oscillococcinum won’t help his cold. But the $5 bill might make him feel better.
It's like the other day. I bought 4 boxes of Vick's Sinex. I didn't really need them but I had $4 coupons for them. They are on sale at $5 each so after applying coupons just $4 total and when you buy $20 worth of Vicks you get $10 in register rewards. Actually I only paid $2 since I used a $2 register rewards from a tube of Colgate. Then used the $10 which cost me just $2 OOP (Out Of Pocket) to buy what I really wanted...2 Red Baron's Delux Pizzas (on sale at 2 for $5), a 24 pack of bottled water, and another tube of Colgate (which yielded me another $2 register rewards). Total cost OOP for all the latter was under 2 bucks.