No doubt you can find some trade beads almost anywhere in Africa, though they continue to become more and more scarce. However, Morocco is not really a place where you should expect to find many, and few bargains. The "home" of trade beads is West Africa, particularly Ghana and environs.

In Morocco, I would spend my time searching for locally made beads and traditional beads/jewelry of North Africa—their fabulous enameled silver, coral, amber (admittedly imported, though they probably think of most of this as "theirs"), and also unique beads such as carved wood, scented paste beads and the like, and beadwork. There are also new local beadmaking industries, some of which make unique or unusual products.

Be on guard for the ubiquitous newly imported beads from India and China, that are neither trade beads nor traditional elements.

Have a great time.

Jamey