As far as I know, the wordpress blogs are for free. You can just register at http://wordpress.com/
But if you have a ASP.NET hosting, why you don't host the blog by yourself wit a blog-software like http://www.dotnetblogengine.net/
This way, you have all possibilities to adapt the blog to your needs.
Hope this helps.
p.s.: I allready use blogengine.net by myself: http://blog.dotnetcorner.ch/