A POS system, meaning point of sale, records retail sales transactions. If a shop owner doesn't know how much money is coming in, for what and from whom, it is impossible to do business. He needs the information for inventory control, taxes, and to figure profit and loss.
The best POS system is one that will grow with your business and flexible enough for you to add your own products or services. A small cafe clearly has needs that are different from a fishing tackle shop. You want one that is easy to learn and quick to teach. Many cashiers are just starting out in their careers so basic transactions need to be uncomplicated.
The best POS system lets you code discounts and promotions with ease. The advantage to you is that you can track which sales appeal to the most customers. This information helps you decide where to publish ads and coupons. If you get a lot of coupons and promo codes being presented, you know that newspaper or website is a good place to advertise.
POS systems make it easy to change prices. All you need to do is change the price in the master list on the computer. When the product code is scanned or service entered, the new price automatically registers.