WooCommerce

WooCommerce is the most popular e-commerce platfrom for WordPress. From: https://woocommerce.com/:

WooCommerce powers over 28% of all online stores. WooCommerce is now the most popular eCommerce platform on the web

WooCommerce provides WordPress site owners with the functionality

– to build online stores
– setup product, prices, coupons, etc.
– set tax rates and shipping policy