Lifted from Revach.net.
Rav Shalom Eisen, z’tl was a dayan and moreh tzedek in Yerushalayim more than fifty years ago. He was also known as an expert in the kashrus and hiddurim of esrogim and lulavim. As each Succos approached, hundreds of people would appear at his house to show him the arba minim which they purchased.
One year, an avreich approached him with a beautiful esrog, mehudar in all its aspects, to receive R’ Eisen’s approval. R’ Eisen examined it and then shook his head and said, “This esrog is not for you.” The avreich was astounded. He had delved into the halachos of the arba minim, and had spent a considerable amount of time purchasing such a mehudar esrog. Why was Rav Eisen telling him that this esrog was not for him?
He asked Rav Eisen, “Is there an halachic problem with this esrog?
Instead of answering him, Rav Shalom asked him a question, “What do you do?”
The avreich answered, “I learn in a kollel here in Yerushalayim.”
“How much do you get paid?”
The avreich answered him, and told him the exact amount of money he received from his kollel.
“And how much are they asking for this esrog?” inquired Rav Shalom.
The avreich answered that they were asking a considerable amount of money.
Rav Eisen said, “This is what I thought from the beginning. You are right; the esrog itself is mehudar. But if you listen to me, I would advise you to purchase a cheaper esrog, and with the remaining money, purchase something for your wife likvod Yom Tov. This is true kavod Yom Tov.” (Chayim Sheyash Bahem)