Make your own Mario costume by obtaining a pair of blue overalls and a red long sleeve shirt to make the base. Cut out a white circle and a red capital letter M, and glue them to a red hat to make Mario's cap, finishing with a fake mustache.
Though long sleeve t-shirts are more accurate to recreate the likeness of the character Mario from Nintendo's "Super Mario" franchise, you can wear a short sleeve T-shirt or a button-down shirt as well. When shopping for overalls, focus on a rich, darker shade of blue rather than a light wash or other color. If you are unable to find overalls, wear a pair of blue pants instead.
Another important aspect of a Mario costume is the hat, which is also red and features his initial on the front. The easiest way to create this hat is to purchase any red baseball cap and make the white circle and red "M" out of felt or construction paper. After forming the costume, affix a fake, bushy black mustache to your face and don a pair of white gloves. Optional accessories include a plunger or a toy representing an item or character from the game.