Many people may be impressed by online stores like Amazon, Staples, Walmart et.al. They have created online stores with multi-million USD sales which are very successful and they seem to be our of reach. This however is not the case. Most of their success is based on the fact that they did a lot of advertisements and campaigns and today everyone knows them. In terms of what is the technical base of their online store, anyone can create something quite similar or maybe even better at little or even almost no cost.
Magento for example is an open source webshop and the basic requirements are simple: A hosting provider with PHP and MySQL, which is available from 10 USD a month. If you care to design and adjust the shop yourself so that it is not the out-of-the-box Magento sample store, you can save yourself a lot of money and create very attractive and stunning online shops. Even if you have someone do the shop for you, the costs remain manageable and you could reach customers all over the world easily.
There are numerous open-source eCommerce solutions but I focus on Magento as it is the one that offers the most complex functions if required and it is very widely used. However, from a user point of view it is rather easy to use and great online stores can be created with it. I can offer you turn-key solutions from scratch to a fully operational online store.