What you needAssorted Fabrics
Use a old black dress from a thrift store. You can then buy some satin or black fabric to make a witches cape.
Use cardboard to make a hat, or purchase one from a store.
Add a long black wig and paint on a few facial warts with an eye-liner pen.
Use some old clothes and using scissors slash the clothes to make them look like they are ripped. Using some brown fur, cut it up and glue it on the hands and neck. Use glue suitable for the skin such as non toxic PVA wood glue, which just washes off in water.
Wear a black suit and then use a large square of black satin to make a cape.
Wearing white clothes as a base, wrap yourself in strips of white fabric or bandages.
Wear a red tracksuit and make some horns and a tail out of cardboard.
Use green leotards as a base. Add lengths of vines, or using crepe paper cut out leaves and glue them onto the leotards.
Spray paint some clothes using silver paint, or wrap yourself in lengths of tin foil.
The opportunities are endless, all you need is imagination!