When you buy a bottle of artichoke hearts, you're also paying for the liquid that surrounds them -- so don't throw it out. You can add it to dishes as an extra bump in flavour.
Since the liquid is usually made up of oil, vinegar, herbs and salt, they can be used anywhere you're already using each of these components. For example, you could use the artichoke liquid as the base of a salad dressing or in place of olive oil in a pesto, long after the artichokes that came in the bottle are gone.
This way, you get more for your money and add tasty, fresh flavours to your meal. You can use the liquid from bottled olives and sun-dried tomatoes the same way.