eCommerce (Some Free):

Mal’s e-commerce is a FREE Shopping Cart Service: http://www.mals-e.com/
Free Shopping Cart Software for Joomla! & Mambo: http://virtuemart.net/
Create your own Online Store for Free with Free Webstore: http://www.freewebstore.org/
eCRATER.com is both a free web store builder and a free online marketplace: http://www.ecrater.com/
Ubercart is an exciting open source e-commerce package that fully integrates your online store with Drupal: http://www.ubercart.org/
Free Shopping Cart Software: http://www.1freecart.com/
ShopSite Shopping Carts (Trial): http://www.startlogic.com/product/shopsitestarter.bml

osCommerce Online Merchant is an Open Source online shop e-commerce solution that is available for free under the GNU General Public License: http://www.oscommerce.com/
Zen Cart™ truly is the art of e-commerce; free, user-friendly, open source shopping cart software: http://www.google.com/search?q=free+ecommerce+&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

35 Free High-Quality E-Commerce Templates: http://www.smashingmagazine.com/2009/01/25/35-free-high-quality-e-commerce-templates/
References :
Payment Gateways:

6 Payment Gateways Reviewed: http://www.sitepoint.com/article/money-where-mouse-is-gateways/
Ecommerce Payment Gateway Primer: http://www.websitepublisher.net/article/payment-gateway/
What You Should Ask A Payment Gateway Provider: http://michellenewman.wordpress.com/2007/07/19/what-you-should-ask-a-payment-gateway-provider/

Ron

Im web designer check my portfolio

skype: pcraddy
msn: admin@inked-world.com
References :