Shill

compare

(an accomplice at a confidence trick)

comparsa

(an accomplice at a confidence trick)

prestanome

(a person paid to endorse a product favourably)

uomo di paglia

(a person paid to endorse a product favourably)

brogliare

(to promote or endorse in return for payment)

prevaricare

(to promote or endorse in return for payment)

trafficare

(to promote or endorse in return for payment)