It depends on your industry and customer base. When I was working with one that was primarily female and cost-conscious, that trick worked great. The fact that

It depends on your industry and customer base. When I was working with one that was primarily female and cost-conscious, that trick worked great. The fact that a code existed helped drive organic referrals (the code alone was enough to route traffic to me instead of a competitor). Don't make it permanent or you definitely are giving money away to Googling cheapskates. Change it often-- people are excited by novelty anyway.