The Sinclair sign and price reflect on a Packard that appears to be having some tailpipe work done. As whimsical as it seems, early stations did exactly this--there were no service bays. Better equipped ones had an outdoor ramp, but the mechanic still frequently worked on the ground.
More info:
www.garysgayparita.com. Note: My images from this location are only available as photographic prints, not as merchandise.