After reading the above two comments, I wish I'd remembered to mention the DAMAGE the cheap ones do. I meant to SAY it but didnt.
DO NOT GO CHEAP for the reasons mentioned above.

OF COURSE, the way to stop the chips and nicks is to stop driving the car. Cars sitting in garages do not get nicks, dings or suffer from UV damage. My 07 has not been waxed since 2014 and it turns heads every time I take it out (about once every three months).