Me and wan_wan over at reddit have been trying to figure out how to setup this kind of pricing rule. http://www.reddit.com/r/drupal/comments/xvnu8/drupal_commerce_buy_x_get_...

Here is what I'm trying to achieve:

Buy 3 products that are tagged on sale and get the 3rd product with least price free. Basically a "buy 2 get 1 free"

The consumer gets to pick the item, but if the product is not on sale doesn't matter how many they have in cart, it should only count the ones tagged on sale.

Has anyone here setup pricing rules like that?