Some powder distributors offer discounts to FFL holders. One example is Black Hills Shooter Supplies.
They sell Winchester, Remington, and others bullets and brass. They sell Hodgdon, IMR, Winchester, Accurate Arms powders but for a full list of their products you need to visit their web site and maybe even call them. They DO NOT sell retail but only to FFL holders. Their prices are competitive and for powder they include the Hazardous Materials charge in the pricing (no extra fee per shipment). They will sell powder in quantities as small as 10 one pounds can or one 8 pound jug. They also have better pricing for truck shipments (over 100 pounds of product).
I am in no way connected to BHSS and only offer this advice based on my personal experience with them.
Again, for more specific information contact them. If you call you actually get to talk to a real person.