discount ticket; reduced fare ticket
A ticket sold at a lower price than the standard fare, commonly used for transportation, events, or attractions.
I bought a discount ticket at the station counter.
This discount ticket can only be used on weekdays.
割引券 is a discount coupon or voucher, often for a specific amount or percentage off, while 割引切符 is specifically a discounted ticket for admission or travel.
前売券 is an advance ticket, which may or may not be discounted; 割引切符 explicitly indicates a reduced price.
Compound of 割引 (discount) and 切符 (ticket).