I had ordered the blond wig for another project, and fell in love with it, unstyled. The night before SakuraCon '09, I was looking for a third costume to take along, and while trying on this wig, realized it looked a LOT like Aya. I was sold after that.
Not much to really say as far as 'construction'. This falls under the same Ghetto Cosplay category as Light Yagami, and my first Misa Amane costume; After deciding to cosplay Aya, I did a quick online search. The most prominent images I found were of her black dress. I ran down to the thrift store and combed the racks until I found a dress that was the right style and, coincidentally, exactly my size. I purchased it for 10 dollars, took it home, and got to work. I split the seam on one side, and re-hemmed it, to get the split in the dress. I then spent a couple of hours tediously picking off all of the beading on the dress. The shoes, while not perfect, were the closest thing I already owned. The gun was borrowed from Kayla.