When I went to buy a regular zipper the other day, there were two different displays. However, I soon discovered that there was a huge display of the separating zippers, compared to so few of the type I wanted.
Many of the separating zippers were labelled as "costume zippers". Some were the larger metal teeth, and some large plastic, while some the smaller plastic and even smaller metal teeth. So many different colours and lengths.
Perhaps you will find the same thing when you go to your store to check them out.