discount fare; reduced fare
Used for transportation fares that are lower than the standard price, such as advance-purchase discounts, round-trip discounts, or special promotional fares.
If you book early, a discount fare will be applied.
Is there a discount fare on this route?
割引 is a general term for a discount or price reduction, while 割引運賃 specifically refers to a discounted transportation fare.
運賃 means fare or transportation charge in general, without specifying whether it is discounted.
advance purchase discount fare; APEX fare
Compound of 割引 (discount) and 運賃 (fare).