One technology that's becoming quite common in grocery stores and other large retail establishments is the self-checkout station. These usually consist of four or more kiosks, each with a scanner, a touchscreen monitor, a card reader, slots for taking and dispensing cash and areas on which to bag or place your purchases. There's generally one worker overseeing a few kiosks, and the customer does the rest -- scanning items, typing in the codes of produce and bagging the groceries. If something goes wrong, the worker will be signaled to come and help so that the transaction can go forward.
There's concern that self-checkout will lead to job losses for some of the millions of cashiers in the U.S. -- there were around 3 million in 2013 [sources: Bureau of Labor Statistics, Thibodeau]. This is an issue that comes up whenever something is automated and only time will tell if they take a major toll on the job market or simply shift workers into other jobs. But some stores are giving them up due to customer service and job loss concerns, including the grocery chain Albertsons. Many people prefer to deal with a human being, although some prefer self-checkout.
Another disadvantage of self-checkout is the greater risk of theft. As an anti-theft measure, many of the systems weigh or otherwise sense the items you've put in the bagging area and check that against what you scanned. Of course, thieves will try tricks like weighing non-produce items as produce in an effort to sneak away with product. Some theft risk can be reduced with video monitoring software that can quickly alert a staff member to perceived wrongdoing, or conveyor systems that scan items quickly and automatically, making it harder for would-be shoplifters to slip things by the scanners.
Advantages include shorter lines and quicker checkout times, at least provided there are no complications. Ikea has actually opted to remove them from stores in the U.S. because they were causing longer checkout times due the difficulty most people had getting their items to scan.
But these kiosks are becoming more and more prevalent, and will likely improve over time. One expected improvement is scanners that actually recognize your purchases rather than relying on barcodes or keyed-in product codes.