How do I setup a buy x get x free option

Hi there,

On my site I want to create an discount where you can buy 2 items and get 1 item for free.

I've seen the solution where you set a different price with a minimum of x items, but then when you add more than the minimum amount of items, that price stays the same.

For example: Let's say an item costs $10,-. You set a price of $20,- with a minimum op 3 items. When you add a fourth or fifth item the price stays $20,-. So every item over 2 is free.

How do I go about this?

With kind regards,
Rachel Walraven