Is it permissible to purchase mobile phones offered in the market at very low prices, and does their cheap price indicate that they are stolen, and consequently, would the buyer incur suspicion or sin?

The cheapness of a device does not necessarily mean it is stolen, and the buyer is not required to investigate the seller's ownership. However, if there is a strong presumption that what the seller possesses is stolen, it is not permissible to buy from him; because that would be assisting the thief in sin and aggression, and because the sale of stolen goods is invalid, as one of the conditions of sale is that the item sold must be owned by the seller. Indeed, Alish mentioned that what is intrinsically unlawful in the possession of an usurper or thief is not permissible to buy from him, and whoever does so is like the usurper. One should avoid buying if doubts arise about the seller, acting upon the saying of the Prophet, peace and blessings be upon him: "Leave what makes you doubt for what does not make you doubt."