These are not official, so I wouldn't look for them in Krause. Maybe soon in the "Unusual coins".
Joel Anderson sells them (for more than your price), here's what he says about them:
Quote:
This set includes seven silver 2007 dated 2500 Franc coins commemorating the 100th anniversary of Great Britain's abolition of slavery issued for the members of the West African States. Britain's abolition of slavery put pressure on other nations, including the United States and France, to abolish slavery as well. The coins are privately issued silver Essai (pattern) coin. Each is 27mm in diameter, contains .25 troy oz of .999 fine silver and has a mintage of just 850 pieces each. The coins depicts the heroes of the Abolition of Slavery movement on one side and the issuing nations arms on the other. Included is Olaudah Equiano (also known as Gustavus Vassa) on the Benin coin. William Wilburforce is on the Burkina Faso coin. The seal of the Society for Effecting the Abolition of the Slave Trade is on the Ivory Coast coin. Frederick Douglas is pictured on the Mali coin. Senegal pictures François-Dominique Toussaint Louverture. Togo honored French abolitionist Victor Schoelcher. Because the members of the West African States utilize a common currency, they have issued few coins under their own name.