Years ago at the end of a group tour in Egypt, I was walking down to the pool area with a couple of 6 packs of Heineken or Löwenbrau (or something) that I wasn't going to have time to finish off, just thought I'd share them with the other people on the trip. I happened to walk onto the hotel gift shop, where the eyes of the man running the place lit up and he followed me to the back of the shop where he conspiratorially whispered a query about whether I wanted all the beer.
I was a little puzzled and responded with something sage like "Huh...?"
"I give you one of these statues for one beer...!"
"Well, I'm not sure...."
"I give you TWO statues for one beer...!"
By that point a colleague had joined him, his eyes sparkling as well.
"Yes, we give you TWO statues for each one beer...!"
Now, seeing that the little statues usually sold for $4-5 each around Cairo, and realizing that I had neglected to grab as many gifts as I should have for everyone back home...
Well, you can guess what happened. I ended up one 6 pack lighter and 12 statues heavier for the trip back home. The two guys scurried off surreptitiously glancing over their shoulders with guilty smiles on their faces.
In retrospect, I've never felt like more of a drug dealer in my life....

. Not sure if it was actually illegal, it didn't cross my mind at first.