reward money; honorarium; gratuity
Money given as a token of gratitude for a service or favor, often in formal or professional contexts. Can be a reward, honorarium, or tip depending on the situation.
I received 10,000 yen as an honorarium for the lecture.
I gave reward money to the person who found my lost dog.
Compound of 謝礼 (gratitude, reward) and 金 (money). The word transparently means 'reward money'.