If you have the money, the best deal is to actually buy the better (or best) grade you can get. The feathers are longer, so you get more flies per feather, and there are more feathers on the skin. When you price it out per fly, it's actually cheaper to use the good stuff.
Personally, I'm on such a tight budget that SWMBO would have kittens if I spent that much money on some feathers....
Now, if I had a stash of several capes/saddles back when the hair craze was at it's prime, I could have financed a trip to Patagonia, or made a good down-payment on a home.....