So I kind of put this off way too long and now I'm in a bind. I need a decent Sith robe by Halloween -- so somewhere that offers very fast shipping ideally (unfortunately most places show estimated shipping dates into November). Budget is flexible somewhat.
I'd suggest going to the store, buying black fabric, and layering it over itself apon yourself in order to accomplish the look of a Sith's robe inexpensively and quickly.
The problem with just buying fabric will be that it usually won't be wide enough. Walmart has black safety pins and black sheets. You can probably rig something up with that and a hooded Halloween robe.