You should ask the Shop-O-Mat about the empty pedestal. That's where the Golden Dragon is but he is watching you. Ask more also. He says you can try the gadgets (not the Golden Dragon, though) before you buy.
This is the low-spoiler guide for "Get the Golden Dragon of Invisibility" puzzle in Chaos on Deponia. Unlike in normal walkthrough, you get gradual hints on how to solve the puzzle. Click the big button below to see your first hint. If the hint contains a spoiler, you will be warned about it before clicking.