This Open Source project started in 2003 as blogging tool. Well-architectured personal publishing system that based on PHP and MySQL. There are huge community around the Wordpress who it to be the largest self-hosted blogging tool in the world.
Custom website on WordPress usually costs from $1,000 to $15,000.
WordPress also works well for eCommerce with a free WooCommerce plugin. Especially if you are just at the beginning of your business. Simply install a shopping cart plugins, customize them to your requirements and your store is ready to receive orders. Operate orders, manage coupons, create reports, inventory, linked products, shipping, settings, add-ons, add tags and categories to all of your products effortlessly. For huge projects better suits Magento.
Stores on WooCommerce: UCanon, CSS Tricks, AdventureFeeds, PagePink Pro4Mance, FilterGrade, Shareware on sale.
But also there is a common situation when WordPress uses to handle site and blog chapters, while store is running on other platform like Magento;)