Is it permissible to double prices in sales to non-Muslims or visitors coming to a Muslim country? And is this earning considered lawful and the money permissible?

The fundamental pillar of a sale is mutual consent, free from deception and fraud, as Allah Almighty says: "But it must be a trade with mutual consent among you," and as the Prophet, peace and blessings be upon him, said: "Indeed, a sale is based on mutual consent." It is permissible for the seller and lessor to differentiate between buyers and tenants according to circumstances and supply and demand. The seller may also show leniency towards a Muslim, a needy person, or a poor person, unlike others. It is not permissible to deceive the buyer or defraud them in prices, whether they are Muslim or non-Muslim.