How much will it cost to go from Las Vegas to Niagara Falls, New York? READ DETAILS?

So I would like to know how much a plane ticket from Vegas to Niagara falls, ny, back to Vegas would cost. I will be staying in new York for about a week and I'm staying with family. But I would like to know how much it would cost to rent a car for 3 days because I am going to NYC. I would like to know how much money 1 room would cost for 1 night (in a 2 star hotel) also how much money I would need to go in the shops. I wouldn't be going in the high end shops, we will just be walking around the streets going into the shops and I will be getting a few momentos from the city. I am going to be going next year. But just give me prices that it would cost now. Thanks sooo much!!!