Some of the rotors I have seen lately were Chinese made. Very cheap price. Customer brought them in from an NAPA store.
They had no crosshatched milling marks and were instead a "record player finish" or standard lathe finish like a refinished rotor.
Once bolted up and torqued onto the hub, they had excessive runout (.015+). This is way out of spec for new rotors.
Be sure to find out what you are buying by asking the salesperson to physically inspect the the rotors. If they have the crosshatched finish, you have a pretty good idea that they will be good quality. Remember, they are only brakes!