Working Demo

Demos of every theme with Woo-commerce compatibility is also a Woo-commerce demo.
You can check the ones supplied by the plugin’s developer WooThemes:
https://www.woothemes.com/product-category/themes/woocommerce/

And for a back-end demo, you can test all of those WooThemes’ Woocommerce themes in the dedicated Playground by creating your own test site:
https://test.woothemes.com/