You can (for the most part) produce bosons (e.g. photons, aka light), individually or in big piles, out of thin air. You cannot produce fermions (e.g. electrons, protons, neutrons) out of thin air like this. To make an electron, you need to also produce a positron or do something else that satisfies the various conservation laws. You can make an electron-positron pair in a collider, but doing this in large amounts takes absurd amounts of energy.