well, there's a lot of free themes available for wordpress. some of them are actually pretty good. couple of popular free ones are swift and arras.
http://wordpress.org/themes/swift-basic
http://www.arrastheme.com/
Problem with the free ones is sometimes they don't get updated and become obsolete or there will be a security issue that goes unpatched. Framework might not be as good as a custom template that you create from sratch but there's some advantages. You can get sites up and running relatively quick and you can customize relatively easy with child themes. They usually use hooks for customization so sometimes it's easier than trying to modify the code yourself.
Right now I'm using a free theme for all of my sites but I've been looking at picking up a framework/premium theme so it's less work for me. I'd rather spend my time putting out quality content. I've also thought about picking up the genesis framework. yoast has a positive review for it:
http://yoast.com/review/genesis/
It's probably best if you can find a responsive theme so your page looks the same on mobile devices. If you want to build your own theme using some free barebones I think you can use something like roots or underscores.
http://www.rootstheme.com/
http://underscores.me/
I don't really know that much. I've read a lot of articles and stuff on forums/reddit. Maybe someone else has suggestions. I use the income from my sites for beer money so I'm happy.