Yes, making a series of Cart Discounts would be the way to accomplish this. We can now support setting discount thresholds by the total unit-quantity in the cart, which may be a bit easier to figure if all your products are the same price and get the same buy-2-get-1 discount, so e.g. you could create a series of discounts like this:
- $25 off the Item Total when Minimum Items in Cart is 3;
- $50 off the Item Total when Minimum Items in Cart is 6;
- $75 off the Item Total when Minimum Items in Cart is 9;
- $100 off the Item Total when Minimum Items in Cart is 12;
- etc. going as high as you wish.
You may decide that if someone is ordering a huginormous quantity (more than you would ever reasonably expect), they might as well just get a flat 33% off every item rather than having to order in threes to get every third item free, and this would be the last discount in your series, to cover all orders of that quantity and larger, e.g.:
- 33% off the Item Total when Minimum Items in Cart is 30.
One final note: when you want to edit or delete an existing Cart Discount you've created in Seller Admin > Cart Discounts, just select it from the menu there and click Load to view and edit its settings (or Delete to do that). Always remember to click Submit to save changes after editing any settings.
