In the bad old days, setting up shopping carts and e-commerce systems was both time consuming, extremely complex and expensive. They still are though no where near as bad as it used to be. In any event, you should be sure that selling on line is an important element to your business and then plan everything carefully.
There are many more options available today and a couple of them I use will fit nearly any budget. This is a case where there are lots of solutions so it is vital that we determine exactly what you want to do and then employ the correct tool. No reason to drive a thumb tack with a sledge hammer. On the other hand, trying to do everything the cheapest way can be counter productive as well.
I can help you analyze what you want to do and what will do the job for you.