Woocommerce has certainly become a de facto shopping cart solution for WordPress powered websites. The implementation is easy, the plugin itself is free and it is maintained.
Its popularity is so high that so many popular themes are coming with many Woocommerce file templates bundled with the theme package. I have helped many of my clients with Woocommerce implementation on their websites.
However, the moment you realize that you need a little more than what comes bundled with the free Woocommerce plugin, you need to start spending money. The more you ask, the more you pay.