I just use childhood chalk.... it tends to be cheaper
altho, I think I need to find an oldfashioned (?) chalkholder like the teachers used to have...back when they still had chalk boards!... my quilting helper ( Zipster- the cat) has taken to playing with it ( rolling it off the table ) and chewing on it.... sigh... It is kinda funny when he chews on it... U see, he is a dark grey cat.. and the white chalk REALLY shows up on his face!! hehehehe