I've recently been working with a product called OS Commerce. I was approached to put together an e-commerce solution for a local store, and found this product to be extremely capable.
Like all of the products I talk about on this site, OS Commerce is freely available. It runs on a LAMP (Linux Apache MySQL and PHP) software stack, and is pretty easy to install for the average technical person with knowledge of Linux and MySQL. Once the software is running, anyone can manage it. It's 100% point and click, and new products can be set up or removed with minimal effort.
OS Commerce even works with many credit card payment providers, such as Authorize.Net, Google Checkout, and Paypal. That means you can use the same PayPal account you use with E-Bay, or go with simple credit card processing through Authorize.Net. You can even allow shoppers to decide for themselves.
As with any web store, the challenge lies in creating the content. Photos must be taken, descriptions written, prices determined, and it all must be entered into the application. Once it's all in, OS Commerce can track your inventory, apply tax and shipping rules, and print reports showing your orders for the day.
If you would like a demo of OS Commerce, please feel free to contact me. We have a small demo installation which I can walk you through.