Rewards Program PLEASE HELP!!

[rammac13]

So say I had a buy 5 get 1 free reward for a product offered and a customer bought 3. The only way for the reward to show up in the shopping cart is to have them buy 5 so this person who has bought 3 has no Idea of the reward. Is there a way with the reward program to let the customer know that if they bought just 2 more of the item they would get 1 free? If not what is the use of the reward program. You are just giving away stuff for free.