So we're out doing some grocery shopping last Thursday, and I happened to see the deodorant that I like, and it was on sale. Regular price $4.29, on sale for $2.99. Not bad. Anyhow, I picked one up.
I'd say 80% of the time, we check the prices on the bill as we walk out of the grocery store. The other 20% of the time, we simply forget. But we're normally pretty good at checking.