WooCommerce is the most popular free e-commerce solution for WordPress. Navigate to WP Admin > Plugins > Add New, search for “woocommerce”, and install & activate the first result. 2.4.12 is currently the latest version of WooCommerce. Your first task after activating WooCommerce is to also install WooCommerce pages.
Setting the Shop page
To display your products, you will want to create a page, leave the content blank, and then set the “Product Archive / Shop Page” in WooCommerce > Settings > Products.
Here you can select the page, choose whether you show categories or products on the main shop page, the default sorting, and more.
Adding a Product
To add a product, you need to go to Products > Add New from the left WordPress admin menu.
Once you’re on the Add New Product screen, you will then be able to set a title for the product item, add the description, and also provide all the data information such as price, stock status, attributes, etc.
You can add a featured image in the right column box, and above that set any other gallery images. Any images you add here will be used for the product slider images.
If you would like to create a product where you can select the size/colour of a product check out the Woocommerce Product Variations guide