This is my dress for the next larp battle I'll be a part of. I and two friends should represent witches. I didn't have anything to put on, so we went to a local cheap (used) fabrics shop and bought some. Then I cut out the shape - half the chest girth at the top, flared from the waist.
I added two tucks at the brest (really necessary to fit :-) ) and turned the edges in. I eventually added a tiny lacing to the waist for the front and back pieces to relatively stay together.
I made a "belt" from a rope I twisted thrice around me.
Quite wearable, if I admit that at first I just intended to cut the shape out and put on like that :-P