What worked for me was, when Radio Shack was hiring, I noticed that "Proud To Be A Drug Free Workplace" was sprawled all over their legal paperwork in bold cursive, so I asked, nonchalantly, "So, if I were to be tested, do I need to pay for it? I know they can get pretty expensive."

My boss was like, "Oh, when we test you, you won't have to pay. We'll take care of it when your criminal background check clears."

Gulp. So, Radio Shack does it for sure. I'm prepared to substitute in the near future when they call.