AlanB,
You have two interesting and conflicting points. Both quite true.
There are inexpensive places to acquire items which can be used in fly tying.
AND, by getting them at craft stores or from the scrap of other products you do deny the fly shop revenue.
I have seen fly shops have to go out of business. Like most other retail, the internet makes price the King and the big stores can cut prices more than the little guy who orders less quantity from the dealers/manufacturers. It's a shame to see a small local fly shop close. They offer more than products. They are usually very willing to share info on a wide variety of subjects about tying/fishing. Many of them help young guys with casting assistance, tying classes, etc., etc.
There are always two sides to the coin......