I’ve made quite a few ecommerce web sites, so rather than have a page about each I just chose a good example. I reuse the same basic engine for each ecommerce site, which keeps the costs and time-frame down.
It has all the features you’d expect, with a cart and products organised into categories. Products can be featured on the front page, in a small slide-show, and products can be on special so their prices come up red to draw attention to them, The on special products also appear on a page just for them.
A comprehensive administration area rounds out the picture, which allows the seller to easily review orders, add/edit products and change categories.