It is for a small business, looking for the best solution... Did a search and only came up with very specific question related to ecommerce
I always suggest that a company that is very small start with an open source solution such as DashCommerce. This way you get the development experience of the people supporting that project, plus the tested framework that many other companies are already using. The more people that use the code base the more reliable it is. Also, the more plugin type features that it might support such as tax, shipping, etc.
Take a look at DashCommerce's feature list to get an idea of what a complete ecommerce system should have.
OSCommerce is a well proven, free ecommerce solution, which is easy to set up
You might also consider just opening up an eBay store :) That way you essentially get free advertising, search engine indexing etc.
Yahoo! Stores has one of the easiest ecommerce setups and has low upfront costs. The ongoing fees is how they make their money, and it becomes expensive with more volume.