Get a discount for rating

[Messiahs]

Hi

 

I'm looking for a module to give a custom a discount for rating.

before the customer pays, he should be able to choose whether they are from a valuation.

If that one facebook assessment and product evaluation from there he will get discount.

Does anyone know of such a module?

Just like on this page http://fast2play.de when buying a game.

However, I want to use facebook and a specific rating module

 

Thx