Several polymer types are used as binders for latex paints. Oil paints usually have a drying oil or a modified oil, called alkyds, as their binders. They're also more expensive. You're paying extra money but you're getting more durability and better adhesion. Typically speaking, quality paints have more prime than extender pigments.
Prime pigments are good hiding pigments, while extender pigments provide bulk at low cost.
The most common prime pigment is titanium dioxide, a white pigment found in both oil and latex paints. It's not inexpensive but is imperative for good hiding. Quality paints also have more additives. Additives are included in paint to provide desirable properties. They might make the paint easier to apply, for example, or give it protective qualities.