With an IATAN or IATA card you can get what's called AD tickets. Those are usually 50% to 75% of the fare. It is not always available . The best way to get the tickets are to contact your sales rep from that airline. LOT quite often offers some really sweet fares to travel agents and they have pretty good availability as well.
Even for airlines that are not offering the discounts, contact a sales rep and ask what they can offer you. If they appreciate your business they will take care of you.