Before you can choose between these two types of lenses, you have to understand the difference.
Simply put, prime lenses are lenses with a single focal length. Prime lenses come in a large number focal lengths ranging from wide angle through super telephoto.
Zoom lenses are lenses which have a variety of focal lengths within just one lens. Zoom lenses can have focal lengths which are all within one class of lens, such as the Sigma 10-20mm f/4-5.6 EX DC HSM Lens, which stays solely within the wide angle range of focal lengths. Zoom lenses can also have focal lengths which span lens classes such as the Nikon 18-200mm f/3.5-5.6 G ED-IF AF-S VR DX Lens which runs the gamut from wide angle, through normal, to telephoto focal lengths.