Shape-changing interfaces are promising for users to change the physical properties of common objects. However, prevailing approaches of actuation devices require either professional equipment or materials that are not commonly accessible to non-professional users. In this work, we focus on the controllable soft actuators with inflatable structures because they are soft thus safe for human computer interaction. We propose a soft actuator design, called xBalloon, that is workable, inexpensive and easy-to-fabricate. It consists of daily materials including balloons and plastics and can realize bending actuation very effectively. For characterization, we fabricated xBalloon samples with different geometrical parameters and tested them regarding the bending performance and found the analytical model describing the relationship between the shape and the bending width. We then used xBalloons to animate a series of common objects and all can work satisfactorily. We further verified the user experience about the the fabrication and found that even those with no prior robotic knowledge can fabricate xBalloons with ease and confidence. Given all these advantages, we believe that xBalloon is an ideal platform for interaction design and entertainment applications.