Does anyone know where to get chalk for the Fisher Price Chalk Art Blaster?

Here is a webpage showing what it is a href="http://www.target.com/gp/detail.html/191-4004041-9746552?asin=B001ELR4SU&afid=yahoossplp&lnm=B001ELR4SU|FisherPrice_Chalk_Art_Blaster&ref=tgt_adv_XSMG1060" rel="nofollow"http://www.target.com/gp/detail.html/191…/a