Often our budgets just don't accommodate buying tools. Perhaps because you are only starting out. Or if you are a teacher and you need a lot of the same tools. So improvising is a good thing. Mo Clay has a great tutorial on how to use a plastic syringe ...
What is more, she also shows an easy way to make a colorful mosaic. She chose to just place a slab of the mosaic slices together onto a backing piece. But you could also cut out shapes!
Where to get syringes you ask? You do not have to find a scientific supplier - many craft stores carry them as they are so useful. Or you could buy 5 mL syringes online here.