She can ask you-¿Qué juego compraste?
Answer: Cuestan.
Explanation: Cuanto means How much in english, so the question is asking how much those books are going to cost. Whenever you see a Cuanto in a question like that, assume it's talking about a number of something, or money. So Cuestan means cost, in the terms of "How much does this item cost?".
1. Estamos
2. Estas
3. Estan
4. Estoy
5. Estamos
6. Esta
