I dont know of a website, but you can call Steve from West Coast Shot/Santa Rosa Lead at (909) 390-4841. He seems like a really nice guy and I believe they sell at something like $22 per bag when you buy over a pound. He is located in southern California and Nevada. I just bought 400 pounds from them at $25 per bag.
If you are close to Oregon, I know of a place where you might get lead shot by the ton at $22.00 per bag. I also know of some very nice reclaimed shot available for around $19.00 per bag if you buy a large quantity. I looked at this reclaimed shot last weekend and I could not tell it apart from new.