shill

A person paid to endorse a product while pretending to be impartial.

carnival barkers and their shills, fleecing the rubes

You’ve Got Mail is certainly the basic model for the plot, which finds corporate candy shill Joel ([Paul] Rudd) and indie-sweetshop owner Molly ([Amy] Poehler) regaling their dinner companions with the very long, digressive story of how they met and fell in love.

Any person enthusiastically endorsing a product; especially, one who is getting paid for the endorsement.

On the screen, there was that quack again, playing the shill for yet another drug company.

An accomplice at a confidence trick during an auction or gambling game, such as an accomplice of the seller who bids to drive up the price.

Sniping is necessary because if you bid before the last minute it just gives the shills more time to screw you over.

The pitchman swept his cane in a slow acceleration over the heads of the crowd and then suddenly pointed the silver cap toward Billy and the shill.

A house player in a casino.

There may even be a casino shill sitting adjacent to you. Normally, the casino shills are gorgeous women, and sometimes men, so enjoy the scenery.

To promote or endorse in return for payment, especially dishonestly; sometimes extended sarcastically even to those not paid but strongly biased in favor.

That contractor seems to be shilling for a certain brand of building materials.

That contractor seems to be shilling that specific epoxy.

To put under cover; to sheal.