Voucher codes have become increasingly popular as a promotional marketing tool. They offer consumers discounts and businesses a way to increase traffic and conversions. Traditionally used by merchants and affiliates, voucher codes are now also used on group buying sites like Groupon, which has over 83 million subscribers. The author discusses how voucher codes can be used effectively to build quality links and traffic. Campaigns run by the author using voucher codes have resulted in 1300 monthly visitors, £1200 in revenue on average from the top 10 voucher sites alone. To run a successful voucher campaign requires understanding customer segments, an affiliate scheme, unique checkout codes, and offers with specified end dates.