The good thing about the Himi gouache sets is that you can easily pop out an empty jelly cup and put in a new one. You can buy them in any local art store or online, of course, but I find it easier to buy them offline. For white, you can buy a 100 ml refill bag and it will last for longer (for roughly 3 cup refills as each cup holds around 30 ml), and you don't have to though away plastic cups. Environmentally friendlier option.