All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If what happened between you and the first man was merely an appointment for a sale, after inspecting the cycle, withdrawing from completing the sale due to discovering the market value is permissible, albeit disliked, due to the breach of the promise if it does not result in harm to the one promised. Otherwise, you are obligated to finalize the sale or bear the damage incurred by the other party due to the promise, such as the cost he incurred in inspecting the cycle. In such a case, you should reimburse him for his expenses.
If, however, what happened between you was a valid and complete sale before inspecting the cycle, the ruling differs, and it is not valid for you to annul the contract without the consent of the other party. This entails a set of rulings.
Therefore, we hope you clarify the actual circumstances for a more accurate answer.
Allah knows best.