I’m going to have a buy one get one free deal going on with my novels - I have no idea how its...

I’m going to have a buy one get one free deal going on with my novels - I have no idea how its going to work/how I can give them away for free but the big book of publishing suggests that you should have some offers going or..something. Plus I feel like giving some away before The Blue Bricks Part I comes out this summer. New book related horizons are on the way. However, I only want it to be for people on tumblr ie people who follow me on tumblr and theres no way of working out who bou...