Here is a news release made by the US Mint regarding the sale of the Negro League Commemorative Coin you can read it here.
You probably will not find the coins on the mint site but there are links below for listings of them on Ebay. In addition I posted a link for the stamps. Keep searching around, do not leave out Amazon and Etsy.
You can purchase the Negro Commemorative Coins on Ebay, here are a few.
