I don't know if drug dealers do this anymore--probably not--but they used to give you the first shot free to get you hooked.
According to Karen Kaplan (LA Times, Apr 16, 2014), now, docs hand out "free" samples--but according to the JAMA on Dermatology, this benefits the drug companies, not the patients.
In fact, Kaiser, the VA, the US Military and many private clinics forbid this.
Yet, in 2011, $6.3 billion in freebies were handed out.
Stanford took at a look at this when it came to acne medicine. A quarter of prescriptions came with a free sample.
Surprise--the free sample ones were the ones most often prescribed later.
Also, the free samples didn't save patients much.
The free samples, JAMA concluded, belong not in the doctors' closets, but their dust bins.
I would add to this that sometimes the older, cheaper drugs are as good or even better.