Prime lenses differ from zoom lenses – they have a fixed focal length. To make your subject larger in the frame with a prime you need to walk forwards. Prime lenses are definitely worth consideration. They are relatively simple to build which makes some very affordable, and light to carry.
Unlike zoom lenses, prime lenses need relatively few glass elements and mechanical parts to operate. This is of interest to professional photographers because the image degrades slightly each time it passes through a glass element. Fewer glass elements means that more of the detail and colours of the scene are captured.
Not all prime lenses are cheaper because of their simplicity. Manufacturers take advantage of the greater optical quality to make expensive, high specification lenses where top results are essential. The super telephoto lenses used at sports matches are usually prime lenses.
A good example of a well-known prime lens is the 50mm F1.8. This gives the photographer the opportunity to get started with decent optics at a very reasonable price. Many photographers' camera bags include a 50mm F1.8 prime lens. It offers an excellent maximum aperture for depth of field and good low light performance.