shill
1. noun Someone who promotes or endorses some product, service, event, etc., in an extravagant, misleading, or insincere manner in return for money or some other self-interest. Originally referred to someone who poses as a satisfied customer in order to lure other people into engaging in a swindle or con. It's sad seeing such a respectable actor become a shill for a used car company. I'm not a shill for their amusement park or anything, I just genuinely think everyone would love going there!
2. verb To promote, endorse, or advertise something in such a manner. It's part of my contract to shill for this movie, even though I know that it is a total piece of garbage. I never trust anyone shilling for alternative medicines or miracle cures.