1. I'll buy a new car if I have money.
I would buy a new car if I have money.
I would have bought a new car if I had money.

2. I'll not travel overseas if mom doesn't pay my trip.
I would not travel overseas if mom doesn't pay my trip.
I would have not traveled overseas if mom didn't pay my trip.

3. What do you do if you were rich?
What would you do if you were rich?
What would have you done if you were rich?