Is it permissible to sell an item that was purchased for 200 Riyals for 300 Riyals after agreeing to that?

This transaction is permissible under conditions: You must purchase the commodity and take possession of it before selling it to them, based on the Prophet's (peace be upon him) saying to Hakim ibn Hizam: "If you buy a commodity, do not sell it until you take possession of it," and his saying to Zayd ibn Thabit: "He forbade selling commodities where they were purchased until merchants take possession of them and move them to their own places." It is permissible to promise them to bring it and agree on the price. The second condition is that you should not be their agent in purchasing, so do not sell it to them for more than you bought it unless they are aware of it. Rather, you deal with them as a seller. The third condition is that you sell it to them at the market price, and avoid a significant increase that would be considered an unfair overcharge if they are unaware of the true price.