I have one that cost 8 bucks and it does sit at a slight angle. At the lower heights the angle is less than at the taller settings. I actually like the angle since it gives a little option to how you sit the car. With the front of the car facing you, it can be angled down for a better view, same from the back.
I am thinking about drilling out the rivet holding the legs together and making a few more holes so I can adjust the angle or make it flat just by moving the pivot point.