Praise be to Allah.
The idea of advertising in order to attract business is one of the modern ideas that cannot be regarded as being exempt from the general Islamic principles governing transactions. But because, in many cases, this method of attracting business has gone too far, we have to mention these general principles in detail, paying special attention to the aims of Shareeah and correct etiquette. This includes the following points:
Firstly: the businessman must have a good intention when advertising, i.e. his intention should be to acquaint people with the advantages of his goods or services, to draw their attention to things they did not know about them, and to provide other information that they may need about them.
Secondly: he must always be honest in his advertising; what he says must reflect the reality of the product or service. Honesty is an essential fundamental in all dealings, but especially in selling. The Prophet (peace and blessings of Allaah be upon him) said: The two parties engaged in a transaction have the choice of either going ahead with the transaction or canceling it, until they part. If they are open and honest, their transaction will be blessed for them, but if they conceal things and tell lies, that will destroy the Barakah (blessing) of their transaction.(Narrated by al-Bukhaari, no. 2079 (2/82-83), and by Muslim, 1532 (3/162), from the hadeeth of Hakeem ibn Hizaam). One of the essential means of being honest is to avoid over-praising a product or service or exaggerating about it, for this could go beyond the bounds of being open and honest. The Prophet (peace and blessings of Allaah be upon him) said: Try not to praise products to one another (Al-Tirmidhi, no. 1268), i.e., the vendor should not praise it in order to encourage the one who hears him to buy it, so that the only reason he buys it is what the vendor says. Some of the scholars counted praise of a product for what it is as a kind of insane or senseless speech from which people should refrain. The guideline here is that the vendor should refrain from saying anything which could later result in regret on the part of the purchaser.
Thirdly: the vendor should avoid any kind of cheating and deception in his advertising; i.e., he should not make the product appear more attractive than it is, or conceal its faults, or praise it in terms of characteristics and features that it does not have. All of this is haraam, as stated above.
Fourthly: a vendors advertising should not include any condemnation or belittling of any other person's products or services, and it should not try to cause harm unjustly to others. The Prophet (peace and blessings of Allaah be upon him) said: None of you truly believes until he wants for his brother what he wants for himself.(Narrated by al-Bukhaari, no. 13 (1/2), and by Muslim, no. 45 (1/67), from the hadeeth of Anas ibn Maalik). The guideline here is that if something would cause him distress if it were done to him, he should not do it to others. The Prophet (peace and blessings of Allaah be upon him) said: There should be no harm and no reciprocating of harm. (Narrated by Ahmad, 5/326-327, 313), and by Ibn Maajah, no. 2340-2341, from the hadeeth of Ubaadah ibn Saamit).
Fifthly: the advertising should contain nothing that calls people to be extravagant or to spend too much, because these are things that are forbidden in Islam. Allaah says (interpretation of the meaning):
and waste not by extravagance. Verily, He likes not Al-Musrifoon (those who waste by extravagance). [al-Anaam 6:141]
But spend not wastefully (your wealth) in the manner of a spendthrift. Verily, the spendthrifts are brothers of the Shayaateen (devils) [al-Israa 17:26-27]
Sixthly: the advertising should contain nothing that violates the sanctity of the pure shareeah, such as advertising haraam things or being accompanied by things that are not allowed, such as music and singing, or showing women, and so on.
Seventhly: the advertising should not be so expensive that the consumer has to pay towards the cost of the advertising. It should be brief and to the point, concisely describing the product or service without going to extremes that may cause the price to be raised.
And Allaah knows best.