Goob,
I don't have a phone number, but I think a good place to start would be to call Remington's Lonoke, AR plant. Lonoke produces nearly all of the shot and most of the loaded shotshells that bear the Remington brand.
Next, call the maker whose name appears on the last bag of shot you bought. I am reasonably sure that if you buy in large quantity, the manufacturer will deal directly with you. That ought to cut prices a bit.
For price per pound, check the metals section of the commodity market listing in you local newspaper's stock pages. You can get the per pound price of lead in the same listing with the per ounce price of gold and silver. After you get the current price per pound of lead, divide that price into the cost of the last bag of shot you bought to get the per pound price of the shot. When you contact the manufacturer, expect the quoted cost to be between the per pound price for lead and the per pound price of the shot.
Unless you deal with a particular truckline or delivery service, I'd ask the seller to suggest a shipper. Just don't expect to save money if you chose UPS or FedEx.
Doc Hudson