Craftbot can be used with PLA, ABS, HIPS, Laywood, Nylon, etc. Probably the most easiest-to-use material of them all is PLA (excellent choice for beginners), since its material properties, such as very low shrinkage, inflict little degrade upon your print quality (not to mention that PLA does not emit any toxic fumes while printing).
It is recommended to experiment with different filaments, because there are so many cool and different ones out there and they all possess different characteristics -you might find some filament types that suit your fancy more than others. You can never know until you try!
(Please note that its not advisable to use any filaments that requires a higher temperature than that which may exceed the safe / maximum value of the Craftbot)
PLEASE NOTE! AVOID SWAPPING DIFFERENT TYPES OF FILAMENT TYPES BETWEEN PRINTS IN THE SAME HOTEND! CLOGS CAN HAPPEN DUE TO THE DIFFERENT MELTING POINTS / CHARACTERISTICS FOR USED FILAMENTS.