>I watch the workflows in places like Home Depot. I'm in line while the person ahead of me needs a price check. Why can't they fire up another instance of the invoice form, complete my sale, and go back to the other guy when his price check comes back?

Because they'd then have to hire prople who ask more than $7/hr, and then that'd cost you in the end. Even the current procedure is too complicated for some, and with a high turnover of the staff, chances are is that the white bird (not a swan) at the cash register will have trouble with something because it's only her first week.

Since I can't change their habits and business model, I had to learn a few tricks: 1) make sure there's a barcode sticker on your merchandise. 2) if it won't scan for any reason, don't. Just say you're not buying it.