Someone got tricked into the gold package by their pot dealer it sounds like. A burner is just a cheap as chips pre-paid phone. You go to walmart or a gas station, pay with cash, the number gets assigned at activation (not in the store) and you top it up with pre-paid cards. Very difficult to figure out who bought what in those situations.

This person seems to think they have to buy a burner from a shady person in an alley that may or may not be the FBI. It's like if Michael Scott needed a burner phone...

buy at...places like brick and mortar stores? How would that get you any privacy in the first place? Cameras in the store can identify you. The store could ask you to take your mask and sunglasses off before serving you. And then there's payment tracking. Even cash would have to be laundered before-hand to be safe.