WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.
UI Movement - The best UI design inspiration, daily
Shopify - Shopify is a powerful ecommerce platform that includes everything you need to create an online store and sell online. Try it free for 14 days.
UI Garage - Specific mobile and web design patterns for your inspiration
Big Cartel - Big Cartel is home to hundreds of thousands of clothing designers, bands, record labels, jewelry makers, crafters, and other artists.
UI8 - Carefully crafted UI design assets