I've long made cold process soap. Now I want to make shampoo bars. However, I do not want to spend a ton of money up front -- I want to do a trial run before buying bulk ingredients. My question is about the mold or press, whatever it's called. Is there anything in my soap supplies or household that I can use? I've got loaf molds, single cavity molds, yogurt cups. Do craft supply stores sell the molds? Thanks!