Adding Post Footer for Each Category

Is there a plugin that I can use to add different content to post footer for each categories on my WP blog? I have one but it only add the content to all post. I need the one that can specify which category I want to add the post footer to.

NOTE: I have searched only to find some code. But I don’t understand how to implement those codes as the authors never explained deeper for a newbie to understand.

Thanks.