Oh yeah, you'll find them. This is what I remember, correct me if things have changed.
At IOA, as you enter the park, look to the right just before Confiscos, there is a soda stand and you'll see them in a glass case.
At IOA, they sell them in the Enchanted Oak restaurant across from Dueling Dragons.
At USF, there is a stand in front of the concert area. Walk past Jimmy Neutron, and look to the left.