Benzalkonium chloride (or Benz) pads have become widely used in body piercing and in medical applications where syringes are used because of their superior effectiveness in disinfecting the skin. Benz pads are also preferred over alcohol swabs in that they do not have the drying effect on the skin that alcohol swabs do. While you can probably get away with using alcohol swabs as a disinfectant prior to piercing, benz pads are superior, and often not much more costly to use than swabs.
Benz pads are available either individually or in bulk lots through medical supply houses. You will also find Benzalkonium Chloride towelettes included in quality body piercing kits available from finer professional body piercing suppliers.