I use SubaruGenuineParts.com (Chaplin's Subaru) out of Washington for OEM replacement items. I found their prices to be much better than the local dealership even with shipping. Jamie there is really helpful if you can't find what you need on the site.
I use Subarupartswarehouse.com ALOT for oem parts. They run a sale about once a month where everything is 15-20% off. That's after the typical 10% off parts compared to the dealer. Ends up being 25-30% off. Only downfall is the shipping charge which brings it back up a bit.