Drugs binge in Amsterdam

You are not being very helpful to a young man here, hippy.

I have had some painkillers on prescription and it cost me £12.
If he buy a small rock of crack it will cost him only a tenner and 70% of it will be Panadol anyway, so it's win-win situation...

This is where you went wrong. See, everyone knows school sick bay has panadol and they give it out for free if your acting is good enough. Failing that, your Mum will hit you up.
Job done.