This is a demo site only. A live site would offer more options for colour, size and other criteria depending on the product.  You may schedule sale prices (when they start and finish), specify ‘featured’ items and even manage stock i.e. display an “Out of stock” message when the quantity reaches a set amount.  You can link products for up-sell, cross-sell and grouping (this example).  You can enable / disable customer reviews per product.  Of course, your products may also be virtual or downloadable products for sale.  This is a demo only – many features are disabled.