How to create promotional campaign with 3 or 4 different products to offer as one package?

[Alans]

My question is how to do promotional campaign with 3 or 4 different products?

For example I will offer to get 2 different variations of our products ( A+B) included one article for free (C). If client order this "package" he will get it for reduced price, and also free shipping fee.

How to do that system will know that if customer order A+B that C and shipment will be free?

Do I have to generate new product?

If yes, how to separate this new product in 3 different articles in stock?

Do anybody know it?

I am looking forward for help - Thanks a lot!