From a small Square phone device to a freestanding POS register, your processing equipment depends on your merchant service provider requirements, what systems you already have, and how you want to accept payments. As more stores add mobile options, you may have kiosks or mobile payment devices available in your store, along with a card terminal at your checkout counter.  Although you don’t need special devices for e-commerce payments, many credit card processors may charge different online purchase rates or require you to purchase a separate plan for online services.