Hey Rob,
Thanks for reaching out to us!
You can take a look at this knowledgebase item to see how to change the order of the tickets that you have created for your event.
You could pursue a CSS solution for adding that type of banner. If you are re-ordering the tickets to always have the best deal in the same spot (maybe the first ticket?) then you could use the psuedo-selector “:first-child” on a psuedo-element there (:first-child:after).
Let me know if this helps.
Thanks!