Special offer in checkout

Hi!

I have been falling for the same trick over 30 times now, and now I want a piece of the cake.
When shopping I sometimes fins dome checkouts where I can get special promos depending on order value or etcetera.
For example, just before I click "Buy" I can see "You have an order value over $100 and get these offers" "Blabla skin lotion $10".

I hope you understand what I mean, and I think this is a great way to make people add more products in their cart.

Best regards!

I hope you understood I want this kind of module to 1.5.1.1 or maybe some help finding out how to do it! ; )