Best eCommerce Extension for Joomla

Developing a website in Joomla for a local Box and Paper company and am looking for the best eCommerce extension I can find. Preferable one that isn't too expensive.

While I have developed a few websites I have never included eCommerce in them so I need some help.

The client wants a main "Store" page that has icons displaying categories. Then from those categories a sub category (if applicable). That links to a product page. Preferably they would like to have something like this: http://imgur.com/cSgmbsM

A table that lists all the products in that category, some information about them, pricing and an option to add it to the cart.

If we can't find one to put it into a table form like that then it isn't a massively big deal I just need something that will adjust pricing per unit as the quantity changes. (Order between 1-5 price is $2.00 a unit. Order between 5-10 price is $1.80 unit. Ect.)

Any help would be appreciated.

Well considering I already have the rest of site with other information about their business already built how difficult would it be to transition that to the new platform?

I wasn't complaining? I just was asking a simple question? I don't have much web development experience.

 

Thanks for the help and suggestions!