What is the ruling on offering consulting services at a reduced price, or benefiting from a client who was known through previous work, or asking the client about other offers in order to provide a lower price?

It is permissible to offer services at a lower price than competitors, and there is no objection to presenting the services of a new office to a client of the old office after informing them. It is permissible to ask the customer about the lowest price they received in an attempt to offer a lower price, unless the customer has already agreed and settled with another office, in which case it is not permissible due to the hadith: "None of you should sell over the sale of his brother." It is also forbidden to buy over the purchase of one's brother, or to bid over his bid if the price has been settled between the buyer and the seller.