WooCommerce is an open source e-commerce plugin for WordPress.
WooCommerce’s Drip plugin connects your Drip account to your WooCommerce store, allowing you to track conversions, sales (events) and lifetime value. You can also add a checkbox to let customers subscribe to your Drip campaigns.
Set up this integration directly through WooCommerce.
For more instructions on customizing this integration, check out WooCommerce’s provided docs.