How can the questioner clear his conscience from the money he took from this girl through deceptive means, and what should he do with what he bought with this money, knowing that it is a large sum and he is currently unemployed, and he wishes to purify himself from all that is unlawful?

You must repent to Allah for this sin and resolve not to return to it. Your repentance is not complete إلا by returning what you took, for the Prophet, peace and blessings be upon him, said: "The hand is responsible for what it took until it returns it." If you are unable to do so, then ask for forgiveness; otherwise, resolve to repay the amount whenever you are able.