Does WP works and convert as store? I am running few websites based on other platforms like shopify, magento, but want to set up store based on WP - question is - will it work? does WP platform, themes and plugins support web store needs...?
There are actually quite a few paid plugins for WP that will make it a true shopping site - To name a couple: PHPurchase now called 66 Cart and E-Commerce Plugin. I have used the PHPurchase and it worked pretty well.
There are a multitude of e-commerce based themes and plugins to make Wordpress work as a variety of stores. (For physical products, digital products, affiliate based stores, etc.) It might take time to find what you are looking for but you can absolutely make Wordpress into a secure store AND include Wordpress's built in blog for the news and plugins to increase SEO, social networking, and other various features depending on the type of store in question.
Honestly these 2 posts probably have the best mix of plugins and themes that you'd be interested in: plugins: http://sixrevisions.com/wordpress/top-5-excellent-e-commerce-plugins-for-wordpress/ themes: http://www.tripwiremagazine.com/2011/03/30-best-wordpress-e-commerce-themes.html
I'd recommend Shopp as the best ecommerce plugin for wordpress. It's a lot easier to integrate with existing wordpress websites than other plugins such as wp-ecommerce.
The easiest thing that you can do is just build out the store that way you would like to using HTML tools and then paste the html code into a blog post (or better) or page. For the shopping cart you can just use PayPal buttons which you create in your PayPal account. They give you the code so you just paste that in where you want. Thats an easy way to get started. Then from there you can try any one of the many plugins.
Personally, I will not touch open-source and/or free shopping carts and stores. I mean big shots like Sony and Best Buy have failed to consistently protect their customers' private information. Therefore I have absolutely no reason to trust open-source shopping cart "solutions," and I certainly do not need the liability.
I've used Wordpress for a couple stores. There are many free and paid plugins to use to create an ecommerce Wordpress site. I think the one I've used is WP Shopping Cart which you can find and read more at http://www.instinct.co.nz