Dear Billy,
Im not sure I understand what you mean by "coupon needs to post on every page". If it coupon is a custom post type, you can query with get_posts() and use a loop to show them: http://codex.wordpress.org/Template_Tags/get_posts#Examples
You may also consider using our Views plugin to show lists of posts without coding.
Please let me know if you are satisfied with my answer and if I can help you with any other questions you might have.
Regards,
Caridad