Not only is Shopify a great content management system for your website it has a fantastically awesome iPad/iPhone point of sale system designed to let anybody easily sell goods in stores, on the go at markets or online.

No longer do you have to enter sales twice into your system, using the free card reader that Shopify provides you can

Shopify POS uses the same easy-to-use online store management system as its ecommerce platform, allowing merchants to easily manage all aspects of their business from one place.

Learn more about Shopify POS: http://goo.gl/llnCR6