You need to start searching on ebay. First though, check your local dealership for pricing. I've found that motorcycle part prices on ebay can often times fluctuate and even be higher than retail.
I purchased a $300 subframe on ebay for $50. However, I've seen $137 fairing stays sell for over $200. Lesson is, do your research and don't assume everything on ebay is a good deal, and you'll end up with a great deal.
Good luck,
Anthony