Board Thread:Questions and Answers/@comment-25336950-20150628050951

I've been in pacifist mode ever since I started the game, and have not sent an attack once. However, I've decided to start attacking people, but discovered that I need to research BFB's before I can attack. Can anybody tell me how much money it costs to research it (I'm currently constructing the building required to research BFB's)? 