These limited-function juicers may be manual (hand-cranked) or electric. They're designed to juice wheatgrass and other grasses, herbs, sprouts, and leafy greens. They also handle very soft fruit like berries, grapes, and kiwifruit.
Here are the advantages of wheatgrass juicers:
They're simple to use.
They're one-purpose machines that are good at extracting juice from grass, greens, and soft fruits.
They're relatively inexpensive.
Here are the disadvantages of wheatgrass juicers:
They're one-purpose machines that require another purchase if you want to juice hard fruits and vegetables.
Cheaper models have plastic blades, which are inferior (so be sure to look for machines that have stainless steel blades).
Bottom line: Wheatgrass juicers are a good choice if you want to process only greens and soft fruits. If you want to have the option of juicing other fruits and vegetables along with wheatgrass, put the money toward either the masticating or the triturating juice machines, which can handle everything the wheatgrass juicers can, but with many more options.