do i need to pay extra for Costume Masks?

we are having a play competition  in our school and for that i am going to need a plenty of things .make up and costumes are among the first ones to be needed.we are doing a play where we need animal masks  and yes some of these animals are exotic so getting such masks could be a difficult task for me .i want to ask that whether there are any Costume Masks that are available ,that can be made according to your choice and preference?since these masks are costume made will charges of these Costume Masks be extra than the normal available masks that you get?