A priest costume is one of the easiest and least expensive Halloween costumes to make at home. As holy men, priests dress simply and modestly in clothing styles that you can find at a local thrift store -- if you don't already possess similar items in your closet. A priest dresses casually in a black dress shirt or trousers, or he covers his clothing with a ceremonial black robe. Children and adults alike can take opt out of the scary costumes typically worn on Halloween and dress as a holy figure instead.
Draw a rectangle that is 3 inches long and 1 inch wide on a piece of white poster board. Cut the rectangle out with a pair of scissors. Punch a hole into each end of the rectangle and tie a piece of string around one of the holes.
Dress in a black button-down dress shirt. Pull up the shirt collar and place the white poster board rectangle under the collar. Tie the loose end of the string around the other hole in the poster board. Use double-sided tape to keep the shirt collar attached to the poster board.
Wear a pair of black trousers, socks and dress shoes. Layer a black suit jacket or a black floor-length robe over the shirt and trousers. Dress in a suit jacket for a modern priest look or a robe for a classic priest look.
Wear a large cross necklace around your neck and carry a Bible in your hands to accessorise the costume.