When you are looking for an e-commerce platform, you firstly need to understand your business requirements i.e.
After answering these questions next step is to list down all the features you want to add in your e-commerce. Creating a business model and revenue model will be the right thing to do. Your business model will answer how things will work and revenue model will describe what will be the sources of income.
The next step will be finding a platform completely or somewhat similar to your requirements. Check the features and prices of the platforms. Don’t forget to check the extra benefits you will be getting with the software i.e. free hosting, Technical support etc.
This article from Inc. Magazine will help you getting the overview of best 5 e-commerce platforms http://www.inc.com/bill-carmody/top-5-ecommerce-platforms-for-2017.html
PS. I would recommend you to check websites of all these platforms and make a list of features and benefits they are offering, only then make the final decision.