Abdullah bin Umar reported,

Abdullah bin Umar said, I sold to the Commander of the Faithful, Uthman bin Affan , some property of mine in the Valley in exchange for property he owned in Khaybar. When we had concluded the transaction, I turned on my heels and hurried out of his house, fearing that he might revoke the sale. The established practice was that the two parties to a sale retained the option to cancel until they parted from one another.Abdullah said, Once my sale and his were binding, I realized I had gotten the better of him, for I had sent him off to the land of Thamud, three nights' journey away, while he had sent me only to Madinah, three nights' journey.

عن عبد الله بن عمر قال

بعت من أمير المؤمنين عثمان بن عفان- رضي الله عنهما- مالا بالوادي بمال له بخيبر، فلما تبايعنا رجعت على عقبي حتى خرجت من بيته خشية أن يرادني البيع، وكانت السنة أن المتبايعين بالخيار حتى يتفرقا. قال عبد الله: فلما وجب بيعي وبيعه رأيت أني قد غبنته بأني سقته إلى أرض ثمود بثلاث ليال وساقني إلى المدينة بثلاث ليال.