Do you mean your five free Kindle Select days? Those are gold. Promote them with the various promo sites so that readers will become aware that you have a free book, and if they like the cover / blurb /reviews they'll probably download it. And if they like that buy the next in the series, if it is a series. And recommend the first book to their friends. And join your newsletter. Yeah, I totally encourage you to do that, if that's what you mean.