You can buy payment hardware and supported accessories (like barcode scanners, receipt printers, and more) from the Shopify Hardware Store in the continental United States, Canada, the United Kingdom, Ireland, New Zealand, Germany, Australia, the Netherlands, Belgium, Italy, Singapore, and Spain.
If your business is located outside of these countries, there are two important considerations:
You'll have to use a third-party payment provider to accept credit cards with an external terminal.
You'll have to buy compatible hardware accessories through an external retailer.