Except that one could buy a burner phone and then toss it away after using it. Though the location of the cell tower could be found if the user just pulls the battery and tosses the phone no one is ever going to find it or him.
These days, even when you buy a burner phone, they know where it was bought, and can review the security cameras for who bought it.
You can try some of the seedier places where you pay cash, but they will eventually find those people also and they will rat you out.