Did you know that Sample Pennsylvania offers free drug tests?

Did you know that Sample Pennsylvania offers free drug tests?
So if you ever see a sign that says "free drug tests" then urine sample.

This is a pun. The humor is derived from the fact that "urine sample" sounds a lot like "you're in Sample". This is potty humor, and also a pun.

I will not comment on whether this joke is actually funny or not.