Is your free Shopping Cart software really "free"?

Free and Open Source software is becoming a "standard" in the last years. Giants like Google, Facebook and even Microsoft started to embracing the Open Source for some of their services and products. We, as developers, know that it's possible to provide a product for free and open source and make a good income from it. But we have to think twice about the "free" definition before diving into while it's very easy to find lots of products which are declared as "free" and "open source". Since this is an article posted on Arastta blog, let's focus on eCommerce and Shopping Cart softwares which declare themselves as "free". We know that selling a product or service (displaying the products, adding to the cart, checkout) is the minimum and main part of the process but a shopping cart software must provide more than that to please it's users, both admins and customers. The core is free but... It's easy to find tons of free shopping cart softwares just after googling for it. You can easily install them or setup on the cloud in seconds and start using it. After a while you will realize that most of these softwares are provided for free but their core functionalities are very limited or they have some other pitfalls. You have to purchase extensions, for example even if you want to implement some basic SEO (search engine optimization) configurations. The worst, you may have to pay forever and monthly for that extension if your store is on a SaaS-Cloud based service. Or le