SpongeBob’s costumes are in the store which you can get to by tapping the dollar sign icon on the top of the title page screen.  Once you’re in the Costume Shop swipe on the costumed SpongeBob's at the bottom of the screen to make your selection .  

**Note some costumes are purchased with coins and others are purchased with pages.  Both coins and pages can be earned by playing the game or by buying them in the Shop with real money.