E-commerce from scratch or not
Many of us have been in the same situation before - code-from-scratch (CFS) or use a framework. 
My experience - I started scripting with Perl. And one of the most used module (for web programming) of PERL is CGI. Some considered it a 'heavy' module and thus a few had developed a 'lighter' version of it. For a newbie, this could be confusing - which module to use? Browsing the archive mailing lists of Perl, I came across what I still consider a gem of a wisdom - what you don't know matters as much as what you know. 
This perl guru reminded everyone that the CGI module had been reviewed by many developers. He went on to explain how the way strings was handled by C (Perl is made with C) was used by crackers to exploit web apps, but the CGI module had code to prevent such security exploits. He went on to add that NONE of the new CGI modules thats he had come aross had code to prevent this same exploit because none of them were aware about this issue!
And ofcourse, like James Black commented on your question, you need to consider the time factor too. 
When selecting a framework or module:

Look at how old it is.
Look at how active it's developers are (through mailing lists archives, IRC etc).
Do the developers provide good support?
Is it secure? 
Is it popular?
I need to develop a new site with the e-commerce part. I'm here to get some hints from you on which road I should go on.
The site will have a static part which include some static pages and the e-commerce part for sell the products. I'm a Django and PHP developer but this is the first time I need to develop an e-commerce.
I see there's some solutions like Satchmo for Django and Magento for PHP.
There's also some services like Shopify that provide a pre cooked solution.
These are my requirements:

I'll need to give to my site a custom layout/style, all written by me
I'll need a nice admin interface for view the incoming orders, the average orders for day and other nice stuff  (I see Magento have a very nice panel for this)
I'll need a feature that reports me the products that are outgoing out of stock
Maybe I'll need to implement a custom payment method
Maybe I'll need to implement a custom shipping courier

Of course I prefer Django instead PHP. Anyone can give me an hint? I've never used anyone of this framework/products.
Thank you.
-- EDIT
Deadline is 3 months. Budget ~7500 $. I've three months for finish it.