Sanding, Primering Car before Paint??

[juantonwan]

I roll painted my car about two years ago. I want to get it repainted but don't want to pay a whole lot.

I was considering Maaco, but I want to sand and possibly primer it before hand. I was curious what I should do.

Should I sand the entire car down to the original color. Then leave it all scuffed and let Maaco paint it?

Or should I sand it down to original color, then primer it, then let Maaco paint it? Thanks