This is the best FREE WordPress themes should use for 2013:

Landscape

Landscape is a simple, responsive WordPress theme. Perfect for photography sites.

Shortnotes

Theme design is optimized for proper displaying on iPhone and iPad.

Siren

Siren is a responsive WordPress theme. This responsive theme is built upon the responsive grid system  called RWDgrid .  The theme will adjust itself to fit on various display devices. The content will adjust between 1200px for widescreen desktops to 300px for mobile devices.  This is a WordPress 3+ ready theme with features like custom menu, featured images, widgetized sidebar, and customizable call to action section , jQuery image slider on the custom homepage template. Theme also comes with an option panel.

Satu

One-column elegant, beautiful and responsive personal WordPress theme. Perfect for personal blog or  even photographers to showcase their portfolio.

Gallery

The Gallery theme has been rewritten from the ground up to be faster and easier to personalize.

Gridly

A free minimal & responsive portfolio theme ideal for graphic designers or photographers.

Underfire

Underfire is a free premium WordPress theme for game, gadget related blogs. This is a stylish WordPress 3+ ready theme with features like custom menu, featured images, widgetized sidebar, and jQuery image slider on the homepage. Theme also comes with an option panel.

8. Spun

Spun is a clean, lightweight, responsive theme that steps out of the way to put the focus on your content.

Spun looks best if you set a featured image to represent each of your posts on the blog index and archives. If no featured image is assigned, the theme will attempt to pull the first attached image from the post. If the post does not have an image attached, the post title will be displayed.

Deux Milles Douze

…Now that child themes can also be on the WordPress repository, I thought I would share it. Deux Milles Douze, the French translation of Two thousand twelve is the result. I opted for a change of colour and moved a few things around.

Great

Great is a traditional, magazine-style WordPress theme. With a clean, minimalist design and all the usual MyThemeShop features, Great is optimized to help your blog stand out from the crowd and dominate the web.