A door hanger business is in the trade of manufacturing wholesale door hangers or custom door hangers (using a specified door hanger design) for those who wish to market their services or products on a wide scale.
Door hanger flyer distribution is a clever direct marketing technique that is inexpensive and does not require a good deal of time.
A door hanger printer or large door hanger print service can provide sample door hangers and door knob hanger templates--a free door hanger template is a great way to get an idea of the most popular and effective door hangers.
Try a discount door hanger business if you do not wish to invest too much into a less than targeted market audience.