A visit to a hardware or department store should yield the basics necessary for simple cake decorating. The following is by no means a complete list of all the decorating tools available, but these are the basics you can find and use easily. For simple and elaborate cake decorating equipment, go to www.nycake.com.
Pastry Bags: A 12-inch bag is easy and comfortable to use for piping decorations on a cake.
Coupling: A two-piece insert for the tip of a pastry bag. It consists of a plastic tube with a threaded (like a screw) end inserted in the bag. After a tube is placed on the end of the coupling, a plastic ring is screwed around it on the outside. This allows you to change tubes from the outside of the bag.