I am looking into this myself. Where are you based (I am in Molalla), where do you shoot?
The recommendation that I got was to go through one of the local clubs that run black powder shoots and see when they are doing another bulk order.
Other than that, if we can get enough people in this area to join together for an order, we can get things cheaper.
Anyone interested in American Pioneer? I have found I can get a flat (12 cans) for under $200.