The Quran is the word of Allah (swt), this means that no human can put a price on it. Even if I were to buy to Quran with billions of pounds/ dollars, that amount is still not enough. According to my dad the Quran is gifted and one gives the person who gifted the Quran an amount of ( obviously not as valuable as the Quran) money back as a gift. But when one gives money as a gift in return for the Quran, the intention shouldn't be buying and selling.