Hi,
There are a couple of "open source" ecommerce solutions
available (usually FREE) from your web host.
oscommerce and zen cart are two (based upon the same
platform). There are others too.
With these you can add, change products, pricing, terms, etc very easily.
I provide oscommerce as well as agora shopping
cart with my hosting packages.
http://www.vwebworld.com/vhost.htm
The advantage of the "open source" solutions is they
are very portable should you decide to change web hosts
you won't have to start over and create your online store
from scratch.
If you have any questions about this, do not hesitate to contact me.
A store using Zen Cart:
www.houseofjerky.net/shop/
~Roland