Here is the ebay item number for the guy selling new ingots of the 250 deg. MP Bismuth Rad. Shielding Alloy, for just under $3.00 a pound. Make sure to get him to agree to a USPS flat rate box first, or the shipping will bite you. Just cut n paste the item number / seller in ebay search. No link used because it will expire with said individual auction.
Listed As: Cert. Radiation Therapy Shielding Alloy Bismuth
Item #: 290459155913
Seller: breyerbme (6173) 100% Pos. Feedback