In general, I recommend WooCommerce for WordPress-powered websites. It works well and is now owned by the same company (Automattic) behind WordPress itself. Hosting arrangements for WooCommerce sites should be a little more robust than your typical site. I often recommend purchasing hosting from WP Engine due to their one-click staging environments.This allows us to test new versions of WooCommerce, etc. on a private staging site before committing to the new version on your public site. The service is a little more expensive, but well worth it.