Drupal Commerce is the leading flexible eCommerce solution for Drupal, powering over 60,000 online stores of all sizes.
Drupal Commerce 8.x-2.x is a stable release. It is usable for production websites.
Use Composer to get Drupal + Commerce with all dependencies.
Drupal 8.4.0 or newer is required.
composer create-project drupalcommerce/project-base mysite --stability dev --no-interaction
See the install documentation for more details.