I have a house that I bought to rent and if I get the right price I will sell it.Do I have to pay Zakah on the house? If yes, do I calculate the Zakah from the price I have paid or from the market price that is totally different?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

You are not supposed to give the Zakah of this house unless you have a firm intention to sell it. In this case, you should pay its Zakah on a yearly basis according to its value in the market every time the Zakah is due on it and regardless of the price you paid for it.
If you have no intention to sell it, then if the money you gather from the rent reaches the Nisaab (the legal amount on which Zakah is due) by itself or added to some other money you own or some goods and if a lunar year passes after the money became your own, then you must pay the Zakah on that.
Know that the Nisaab is any amount that reaches the value of 85 grams of gold and its Zakah is 2.5 percent.
Allah knows best.