Re: low cost iaido black uniform?
Along the lines of Mr. Little's post... Maybe there are some "value added" things that come along with spending a bit more and getting it through your sensei? Like your sensei's advice and help in getting the correct size and appropriate gear for your style? And maybe even a few other less tangible reasons why you may want to consider going through your sensei...
That said e-bogu has some nice stuff and is run by some very nice people.