Andy Gan
There are a large number of scripts out there that can handle e-commerce for you... One of the most respected ones is OSCommerce which also happens to be GNU (Free)
osCommerce, Open Source Online Shop E-Commerce Solutions
What your going to find is that no matter which script you use, a reasonable amount of customization will be required to fit the script into your site. Generally, a little bit of HTML will help and definately PHP....
If you tell me a bit about your product and how you want to deliver to your clients, i might be able to make some more speciffic recommendations.
As always Stiney51 and Tamlin have both offered excellent suggestions about hosting... so it sounds like that issue may be solved for you.
Let me know if I can help you further...
Mike.