There are so many eCommerce solutions available today that the answer to this question really depends on your needs. Do you want to run a small store with a few items? Or do you have a website with multiple databases that you want to sell to people in different countries? Or perhaps you want to open an online store in addition to your physical store.
Compare solutions such as Shopify, Lightspeed, Magento, and WooCommerce. The last one is a WordPress platform, so check it out if you're already familiar with that content management system.