One of the best and well-supported blog software we ever used is WordPress. You can download it for free from http://wordpress.org/
or just send an email to support or open a ticket and we will install it for you at no charge. It can be installed in a folder (ex: www.yourdomain.com/blog), on a subdomain (ex: blog.yourdomain.com) or on a new domain (ex: www.widgetsblog.com ).
WordPress is also included with all our WooCommerce based packages.