Each market decides how its discounts combine. The settings live on the market's Discount settings tab and apply to every discount in that market.
Stacking and priority
Single mode applies one eligible merchandise discount, chosen by the best saving for the customer or by your priority numbers. Stack mode combines compatible discounts. Buy X Get Y and bundle offers reserve every unit in their completed sets, so an overlapping claiming offer can use only unclaimed units. Targeted line discounts apply before order-wide discounts; each later percentage uses the remaining line value rather than the original subtotal. Automatic + Coupon controls whether automatic discounts join coupon discounts, while the coupon limit caps how many coupon codes can join.
Coupon limit
The coupon limit caps how many codes one order can use. Its maximum is a platform limit — checkout enforces the same cap, so a saved value is always honored.
Quantity-priced products
Products using quantity-pricing ladders are excluded from discounts by default because the ladder is already their volume price. Enable discounts on quantity-priced products only when you intentionally want both reductions to apply.