Check ebay for some great special offers - up to half price on the feathers refill for quantities of 5 or 10, maybe less for a stock of 20 or 30.
I've come to the conclusion that Da Bird is worth any money - just like good quality food. It's not just a toy, it's psychological medicine, especially for indoor cats. And great physical exercise too. And cats go crazy about it. I'm replacing feather refills every week, because once it's not in perfect shape, it loses its appeal and becomes just another toy. If the stem of one of the feathers is broken, it won't fly the same.
When the stray got into the house and I found myself with a very tense situation between the now 3 cats, and was at a loss, I replaced the refill on Da Bird and that moment was the beginning of the improvement between them.
I once wrote a thread on Da Bird on here - I just can't recommend Da Bird enough. And it's patented, which means you won't find any other brand or wand toy with its aerodynamic unique qualities.
When people come to me for advice, I tell them: Orijen, Da Bird, high places and the best vet you can find.