ZenCart is an open source, PHP/MySQL based Ecommerce shopping cart solution. It's free and the source code is completely customizable by anyone who wants to modify or develop it. As far as open source software goes, Zen Cart is a giant. Even though it's free, it gives some commercial carts a run for their money in terms of services offered. ZenCart is the most easy to install software and is flexible in managing things from the back-end. The admin section is so easily accessible that even a layman can understand the system and start performing tasks in no time. Its proficiency in template designing, development, theme designing, payment gateway integration makes it highly demandable at a global level.