Pricing Rules Based on Other Products Already Ordered
I'm not sure what the best way to proceed is. What I want to do is set the price of a product to zero if another product has already been purchased. It's a one-to-one relationship.
For example, one free scarf for every hat purchased.
What I need to be able to do is say "if the number of hats in the cart is higher than the number of scarfs, then set the price for the scarf to zero."
I'm pretty clear on how to set the price to zero, but not sure how to approach the condition.
Any thoughts would be appreciated.