A freestanding self-propelled device for moving objects. The device includes a chassis having lower frame portions and upright frame portions. A single motor-driven drive wheel is centrally located between the lateral ends of the chassis and coupled to the chassis so as to be pivotable about a substantially vertical axis. The drive wheel is located between sets of support wheels coupled to the lower frame portion of the chassis. In combination, the drive wheel and the support wheels result in the device being freestanding. The drive wheel projects below the sets of support wheels so that the device is supported by the drive wheel and by only one of each set of support wheels at any given time, thereby establishing a three-point contact with the surface supporting the device. A tiller equipped with controls is pivotably coupled to the drive wheel for pivoting the drive wheel about its vertical axis.