Woocommerce is our favourite shopping cart at the moment, its good to develop for, clients love how easy it is to use and it integrates nicely with wordpress.
Xero is beautiful accounting software and is the world’s easiest accounting software you’ll see. It handles all of your business accounting functions from bank reconciliation and financial reporting to inventory tracking and payroll.
Xero for WooCommerce gives you the ability to setup automatic creation of invoices in Xero for your ecommerce sales. After the module is installed and configured each order place in your WooCommerce store is securely sent to your Xero account to keep your records up to date.
All items, shipping, discount, and tax data is sent to Xero. When payments are made they are applied to the appropriate invoice to keep everything in balance.