> Just have exact change in hand! Easy enough in places that incorporate tax into the list price, but this is next to impossible in the US. You'd have to know

> Just have exact change in hand! Easy enough in places that incorporate tax into the list price, but this is next to impossible in the US. You'd have to know what the city, county, and state sales taxes add up to (accounting for any products that have a different sales tax than others!) and then do the math with the weirdly specific percentage(s) that results (again, taking into account that some items are taxed differently!) to come up with your exact change. Try doing that with a week's worth of groceries.