Brakes for my '93 Vert

OK, I need some advice here.
I have a '93 Vert and I have a grinding noise in the drivers rear when I apply the brakes. It will continue shortly after I let up on the brakes. I spoke with my tech and he said that he remembered a lip on the rotor when he did the tires and wheels for me. Dah! Why didn't he say something? :shrug01:

Eckler's has replacement Rotors for $39.99. I checked AutoZone and they are at $66.99. What am I missing here? :thinkin:

hmm, that's a good one. I'd just get them through ecklers. I guess they stock more so they get them cheaper.