Let's look at it from the perspective of a space-faring civ that arrives in a solar system, and you need resources. Would you mine things in a big gravity well

Let's look at it from the perspective of a space-faring civ that arrives in a solar system, and you need resources. Would you mine things in a big gravity well like Earth's and have to pay to get the resources out of the gravity well? Or mine asteroids and low-G moons?