I've seen some super large dollar stores that are making lots of net profit. Just because the items are cheap doesn't mean the net margin is small, because the

I've seen some super large dollar stores that are making lots of net profit. Just because the items are cheap doesn't mean the net margin is small, because the items are cheap to buy too, and they're chains that buy large quantities often directly from a manufacturer to get the best price they can. I think it just depends on what the net improvement is. If they had two checkouts before, that each required a person, and they replace it with 5 checkouts that now require just one person, the cost per person-checkout is 20% of what they were paying before. The machines themselves might be leased or otherwise amortized over significant periods giving a cheap cost per year. If lines of people are waiting for checkout that might mean a much improved experience.