I have gotten into fly tying in a big way for a simple reason. I'm not able healthwise to use the flies and other equipment I have safely and for any length of time anymore. Tying flies gives me an outlet that keeps me in touch with the fishing scene and is definitely not ever going to save me money. I only hope somewhere down the line someone can get further use out of the amount of items that seem to almost appear magically around the tying bench (well, paypal would disagree with the magically).
Years ago when we were out on one of the first excursions with the new to me bassboat I landed a nice fish. Wife looked up from her book as I released it and said, "Oh good, we're down to $10,000 a fish and you throw it back."
This is similar to trying to save money tying flies. I have many hundred flies sitting in boxes and if I figured out cost/fly ratio including those boxes and items on the shelves I'm sure I could buying Rapala lures for the cost of each fly.