We've added another promo code scenario to the CMS toolkit! Now, you can offer a product at a discounted price when your customer buys a specific quantity of another product.
If you've ever ordered 2 pizzas online and been offered garlic bread for $1, you'll know how this one works. 
If you'd like a run-through, check out our document here - Buy X, Get Y for just $Z Promo Code.
