Pretty much if you buy direct from the manufacturer and you buy "enough" of them, you get a good deal. Its been a while since I did it (haven't shot them all up), but I got pretty good deals from Zero bullets on jacketed bullets, cheaper than cast- but the caveat was I was buying by the ton, literally. MG will do the same thing, and they actually are a bit more aggressive as they will give discounts at pretty small amounts (ie a case of 4000) as noted above.
Another thing to look for (more common with rifle) is to look at the manufacturer's site for blemished bullets at discount. They generally have a visual appearance flaw, but shoot fine. Nosler is known for this. Occasionally Midway or some other co. gets a large lot of blems from some company and sells them as such also (midway usually doesn't ID the manufacturer though)