Caesars was still giving them away in the late 1990's or early 2000's. I think it was at the cage in the Forum casino, but they'd only give out one deck per person.

They asked me if I wanted red or blue, I asked for one of each. They said no, so I chose one color. The lady in line behind me told me to wait a minute, then she asked for a deck in the color I didn't have. She gave it to me.