Cosplay advice

Ok, I have to go to an anime expo and want to dress up like an anime male character who is very close to me in terms of looks.

Now, I got short lil bit spiky black hair ( don't think you need to know anything else about me .. nao, I aint fat! ). I was thinking of dressing like Hei from Darker than black as all you need is a mask and a black jacket.

I don't want to buy a cosplay dress from ebay as they are damne xpensive.

Anyone have any other recommendations?