Happily, e-commerce is not the highly-specialized, expensive beast it was ten years ago. With the ubiquity of online shopping these days, just about anyone can easily set up an online storefront and begin selling almost immediately. Online shopping has become a multi-hundred-billion-dollar industry and, with that comes innovation and offerings that provide smaller businesses access to it.
Should I build my own online storefront or use a service?
That depends on a number of things like customer perception, overall cost, ease of use, scalability (will it still be suitable if your business grows) and if there are any limitations to doing one or the other specific to your business.