I have one! Mine no longer functions, sadly. The way it worked was you'd put a coin on its hand and press down slightly to activate. It would tilt its hand up and open its mouth so the coin would slide in. It would then "chew" it, and finally lick its lips. The eyes tilt up when the mouth opens.

I opened it once years ago, and the mechanism is pretty fascinating. The whole sequence is driven mechanically. There's a big cam inside that rotates 360⁰ during a "coin gulp". If I recall correctly, the only "electronics" are a single switch and a motor.