Undertaking transactions according to Hadeeths
14-12-2011 | IslamWeb
Question:
Is the Hadeeth in which the Prophet, sallallaahu ‘alayhi wa sallam (may Allaah exalt his mention), urges Muslims to let people be heedless of each other because Allaah The Almighty lets some of them earn their living from the others, authentic or not?
What is the ruing if someone intermediates in a transaction, giving advice to the seller that his commodity is worth a higher price, or giving advice to the buyer that the good is worth a lower price?
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The Hadeeth that you ask about is narrated by Muslim 
in his Saheeh (book of Authentic Hadeeths), but without the word 'heedless.'
Jaabir 
narrated that the Prophet, sallallaahu ‘alayhi wa sallam, forbade the dweller of a given area to sell at a higher price some goods to a stranger who had not yet entered the market and knows the prices. Then the Prophet, sallallaahu ‘alayhi wa sallam, added that people should be left alone so that each may be able to earn his living and meet his needs. Abu As-Saa’ib narrated that the Prophet, sallallaahu ‘alayhi wa sallam, ordered that people should be left to benefit from one another, and if a person asks his fellow Muslim for advice, the latter ought to provide him with it. [Ahmad: Al-Musnad, At-Tabaraani: Al-Kabeer, Al-Albaani: Saheeh (Authentic)]
If a stranger travels to some place to sell commonly needed goods at the daily price, it is prohibited for the dweller of the same place to tempt the stranger to leave his commodity so that the former would gradually elevate its price and then sell it on the stranger's behalf. This is considered a sin as long as the dweller knows of the prohibition. If he does not have knowledge of it or the commodity is not in demand and this will not cause the market prices to rise, it is not prohibited.
Intermediation in a transaction by giving advice to the seller or the buyer, as mentioned in the question, is impermissible, according to the general meaning of the previous two Hadeeths. This is because the price may be higher in one place and lower in another, and even in one commodity according to its quality. However, if a person sees that one of the parties is to be harmed by serious fraud, or if he is asked for advice, he should intervene and give advice, because the Prophet, sallallaahu ‘alayhi wa sallam, taught us that religion is sincere advice, as was narrated by Tameem Ibn Aws Ad-Daari .
Allaah Knows best.