A ’Buy 3, get 1 free’ discount is (as the name implies) a type of discount where a customer gets a fourth item for free – either a fourth of the same item, the cheapest item, or (very rarely) the most expensive item.

In this case we will make the cheapest item free.

To create a ’Buy 3, get 1 free’ discount:

• Go to Ecommerce > Discounts & Offers
• Click on the Product Discounts node
• Click New discount in the toolbar and open the edit discount view (Figure 1.1)

Fill in the details:

• In the general section enter a name, e.g. Buy 3 – get 1 free!
• In the discount section:
  • Apply as: Product discount
  • Discount type: Percentage
  • Percentage: 25
• In the triggers sections, leave everything as is except the Product Quantity section:
  • Quantifier: Same product
  • Product Quantity: 4

As you can see, this triggers a 25% discount for order line when the 4th product is added to cart, which effectively means that the 4th product is free. Please note that the 25% discount also applies to any further products added to cart.