If you want to make a donation, you must know that you will resemble God because He is merciful by excellence. Hence, He will help you and enlighten you. You will receive a revelation from Him because He will necessarily tell you how much to give, since you act like Him.
However, this revelation isn’t of an angel holding a papyrus scroll in his hands or something similar—such “revelations” are very dangerous and are from the evil one.
You will say to yourself, “I will give 1 €.” Your conscience will respond, “Come on! You should be ashamed of yourself! It is very little!”
Then you will say, “I will give 1,000,000,000 €.” Frightened, your conscience will respond, “Oh, my God—it is way too much. I can’t afford it.”
Starting from here, you will split the interval, perhaps asking others around you, until you will reach a sum where your conscience is at peace and you are serene.
2€? 2,000€? It doesn’t matter. It only matters that the voice of God in you, that is your conscience, says that amount you should give in that situation.
Based on Saint Varsanouphios and John the Prophet