I've gotten most of mine at local thrift stores, sure its not X cut of a vest, but hey it looks cool enough. Atleast on the upside us guys can do that, when it comes to the woman folk they have a harder time finding "something that looks close enough."
I think I've spent around $50 or so on atleast two complete outfits, plus a handful of mix match vests and pants. About the only thing I've special bought was my puff ties which I get from a friend. And a tux shirt, which had the right collar and size for me(which was only a few bucks on eBay).
Now my 24th Reg. of Foot jacket I spend a PRETTY penny on.....