Unless specifically indicated, all discount codes provided, or applied by an automatic offer, are all for 'individual-use' and can only be used on their own in an order. Discount codes or offers can't be combined, and so they can not be "stacked" to be used together in one single order. If you have a code for 20% off and another for 15% off, you can choose to use and apply either one or the other on an order. But they can't be both applied together, to get 35% off on a single same order. Unless specifically indicated, discount codes can't be applied on Sale, Clearance, marked-down or discounted items with any type of price reduction already applied to it from its regular Full Price. In the same way, if by creating a bundle or similar offer, some level of discount is automatically applied at check-out, no other different discount code can be entered to be applied on the same order, to receive a stacked or accumulated discount on top.