A doctor or shrink that will write up a prescription for pretty much anything over the tiniest "medical problem". Basically a medical professional turned "legal" drug plug.
Tom: I stubbed my little toe, I bet Dr. Plug will write me up a prescription for Xanax.
Dr Plug: Here you go mate.
Juliet: Oh shit its' finals week, better hit up Dr. Plug and feign ADHD to get myself some good old Adderall.
Dr. Plug: Here are 30 30mg Adderall pills, I'll up the dosage when you feel normal again.