Disclosed is a sign caddy system for mounting from a hitch receiver of a vehicle. Certain embodiments include a pair of upright tube arrays that are spaced apart such that a tube in one array can receive a first leg of a sign (such as a real estate listing sign) while a complimentary tube in the other array receives a second leg of the sign. Advantageously, users of a sign caddy embodiment can easily transport real estate signs (or other sign types) externally on the vehicle.