Nikon flashes (SB24,SB25,SB26,SB28,SB28DX,SB80DX,SB800) all have GN >=50m and feature auto modes. A second hand one might be the best value for money spent (especially SB28, 28DX or 80DX which are quite compact as well).
Other cheaper choices with GN>105feet and automodes:
Vivitar 285HV (GN120 feet) - which can tilt up and down but can't swivel sideways.
Metz 32Z1 (GN37m)