I have a dream of someday owning a fine silk tophat (that doesn't break the bank). That is why I have subscribed to Heritage Auctions' newsfeed for haberdashery (or is it millinery—I often confuse the two and even after looking it up, I'm not sure).
Well today there were a couple of listings. One was a beat up old antebellum number
that opened for bidding at $21 Yankee dollars (and for that price they also threw in a beaver fur top hat as well, with an old style lamp/torch). The other is one of the most beautiful specimens I've ever seen listed in great condition and pedigree...but unfortunately, it doesn't meet my parenthetical requirements (something something J.P. Morgan Chase Bank).
If you've got $1,000 or so Yankee dollars burning a hole in the top of your head or pocket, this might just be your best investment. I don't, so I'm passing along the bargain (?) to you.
Also, if you're dressing up in honour of/as Sherlock Holmes, recall that this is a much more canonical (if not economical) choice than a deerstalker.