Above on sale for kindle this month - in US at least. Also Martin's Wild Card series has a few volumes on sale. Coretta Scott King's Memoir, House of Cards books, Hair Story, Native Guard (poetry, really good poetry), Chronicles of Kazam, Conversation with Mandela (with Obama) are also on sale.
There are several YA and children's Afro-American history titles as well.
Comixology sale on Transformers, Lumberjanes, Goldie Vance, Star Wars, and Dr. Strange