What is WordPress? A software that provides very easy to you online dashboard to post, manage and mantain a web blog. I recommend it. It is free and will cost you nothing.
This blog uses WordPress. Of course you can purchase blog software that would give you more capabilities and Content management system with even more options.
The main advantage of WordPress is that there are the whole communities of developers and volunteers that will help you to grow. One of them is my friend Kaushal Sheth. I strongly recommed you to visit his blog. It will give you daily information on WordPress and it provides different Themes that you can use for your website blog.