I buy a lot of books from Book Sales so I can't tell which one I last bought. It's hard to resist buying cheap books.
But I guess the last book I bought from a proper shop was Last of Gaderene by Mark Gatiss, It's part of the reprinted books for 50th anniversary Doctor Who set. Haven't read it yet, but I'll get there.
Festival of Death is another title from the Doctor Who 50th anniv series! My mom actually got me this one. Hahaha. The height of my to-be-read pile had already passed me. I really need to pick up the pace with on my reading.