Rewards for ending the Death Curse?

So the party has returned successfully to Port Nyanzaru and is essentially looking for a payday (none of the party surviving knew Syndra Silvane and she is long dead).

Their plan is to approach a merchant prince and tell him the story under a zone of truth. What if any rewards would any of the merchant princes offer the party? I doubt it would be as simple as a big cash payout.

Please give me your suggestions and even complications that might arise from the players trying this.