You will start with Mickey, but can unlock other Tsum Tsums such as Perry the Platypus and Winnie the Pooh by spending coins to purchase gifts in the shop. You can also convert rubies into coins if needed. Purchase the Happiness Box or Premium box with coins to get random Tsums Tsums. The Happiness Box is the standard box can be used to get standard Disney Tsums Tsums. The Premium Box contain Pixar as well as more recent Disney Tsums Tsums.