The best supplies to get started with basic bullet journaling (besides the journal itself of course) are, in our view: (a) a basic black Sakura Black Gelly Roll and (b) pack of Koi Brush Pens.
This is a great starter set for children who want to get into bullet journaling. This provides some wonderful brush pens to add colour and a durable, black pen for drawing, doodling, writing and drawing lines.
NO JOURNAL IS INCLUDED.