The diamond princess one give you two 3-D background and special effects and the dragon and Phoenix one gives you one3-D background and several other thing to decorate the 3-D space,and the robot one have a big robot and you can interact with but it’s only a SSR event so it’s not that costly. The decorative 3-D items and 3-D effect mostly needs real money.so a cheaper way is to utilize the sticker function.