We have worked a lot in order to provide this shopping cart.
We have tried to get things decoupled, in order to have a better maintenance and flexibility.
We have used some design patterns, that allow you to give value to the specific domain of your company and products.
There is a lot to do: @leaphly.
Welcome to the Leaphly Sandbox - a fully-functional Symfony2 application that you can use to play with the leaphly concept.
See the Install the sandbox chapter of the website.
Enjoy!