$500 sounds like a great deal if you ask me. I've seen guys pay over $500 for just the paint protection. Underbody they could charge the world for if they wanted. I've done paint protection install before, I won't ever attempt it again. Did you know Mazda charges over $1,000 for the cx5 front only kit installed? What all is getting protected? All of the bumper, hood, fog lights, headlights, mirrors? My dealer doesn't do paint protection kit installs anymore, we leave it to the pros.