You can put your own treats or home made treats in these balls. You don't have to buy the ones that are sold to put in them. I don't know how safe that plastic is though since it's made in China.
Petsmart is asking way too much for that ball. You can buy it at JB Pet for $9.99.
http://www.jbpet.com/index.php?main_...oducts_id=2766