Your example of the cash register is interesting. Planet money did an interesting story on this, the birth and death of the price tag. It starts with the CEO of Coke, who suggested adding a thermometer to the side of his coke machines to charge more on hot days. This flexible pricing got a huge degree of backlash from generations who were raised on fixed prices, but the reality is that those fixed prices are a result of your cash registers. Where once a store had to hire a clerk who knew the business, the volume of raw goods for the season, the numbers left in stock, the demand for the day, month, or year, the invention of the cash register allowed stores to hire the untrained who only had to enter in a pre-decided, nonnegotiable price. It's a great example of automation.