Looking for undercover cop scene

[DJ Doena]

I have this scene in my head but I can't place it:

Undercover cop wants to buy drugs. Drug dealer tells him it's "50". So the cop starts to pull out a few dollar bills and even some coins to make up for the 50 dollars. Then of course the drug dealer looks at him like he's an idiot and explains that of course it's 50,000! And the cop then is surprised because he doesn't have that kind of money.

It's probably an 80s movie. Mel Gibson, Eddie Murphy but I picture the cop as white, not black.

[DSig]

Yep .. Mel Gibson first Lethal Weapon i think.

[Achim]

Yep .. Mel Gibson first Lethal Weapon i think.

Based on that I found this:

[DJ Doena]

Yeah that was it. I totally forgot that was how the movie began. I thought it was with the trailer scene.

Thanks