I often start buying a bunch of flies a month or so before heading out on a Montana trip.  As you all know, a tiny container of flies can be amazingly expensive.  That is why I buy most of mine on eBay.  I have found a few people who tie a real nice fly and sell them at great prices.  Here, for what it's worth, are my favorites.

Kootenay Lifestyles
I really like this guy.  He is a guide up in Canada and has always provided me with nice flies.  Even with shipping his flies are a great deal.

Wilderness Angler
I have purchased from Wilderness Angler when I couldn't find what I wanted with Kootenay Lifestyles.

Quigs
Okay, Quigs does not sell flies.  He does sell thread furled and silk furled leaders that I really like.

So, there you go.  Three new sources to help reduce the cost of your next fishing trip.  Or, great gift ideas for the upcoming holiday season.