A clean and minimalistic eCommerce theme
Price: $49
This premium theme has a fluid grid layout with a mobile ready responsive design (meaning the theme works perfectly on any device from desktop computers to smartphones). Additional features include beautiful custom product pages, pop-out shopping cart tab, an integrated blog, customizable theme options panel and more.
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Product Page

Link: Gridport WP Theme

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A responsive WP theme suited for business and portfolio sites.
A WP theme with with a plethora of options to modify options such as: styling, colors and fonts. Other features include: 3 Slideshows, 21 predefined skins (which are easy to modify), as well as a dynamic template builder to help you create your customized look.
Price: $40
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Link: Propulsion WP Theme

Fresh and clean eCommerce WordPress theme
Features include a smooth and minimal design suitable for any brand, 4 page templates, compatibility with PayPal and other payment gateways, and an extensive theme options panel.
Price: $79
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Link: Armonico WP Theme

Check out some more themes: Premium WordPress Themes 2012

Clean graphics and an uncluttered design
Wardrobe theme provides exceptional control utilizing clean graphics, uncluttered design, and compatibility with top eCommerce plugins: WP e-Commerce, Jigoshop and WooCommerce. A theme options features is also available for custom editing of the theme.
Price:
Wardrobe Theme Standard Pack: $49
Wardrobe Theme Developer Pack: $99
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Stylish and modern e-commerce theme
WooCommerce offers outstanding features including: integration with various payment gateways, cart, checkout options, detailed shipping settings, admin and reports panel, customer and order management and more.
Price:
Standard: $70 (includes 2 bonus themes)
Developer: $150 (includes 3 bonus themes)
WooThemes Club Membership: $15 – $20 per month
WooCommerce plugin: free
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Link: Coquette WP Theme