no, you don't need to have Data Assist or Data Bridge to build a shopping cart.
using Data Assist can speed up the creation of the catalog pages in your shop, but you can also create them manually using Dreamweaver.
The tutorial for creating the catalog pages are written from the point of using Data Assist, because that is the quickest way to do them.
the Database getting started guide will show how to create a basic set of pages without using Data Bridge:
that you can then add the cart functionality to.