Ben started as a seller on Ebay - ridding himself of unwanted wedding gifts and old junk - to make room for a new baby in his small home near Kansas City. But he quickly "caught the bug" and became one of more than 4.3m people that make a significant chunk of their income from the internet sales site.

The full-time engineer says that in his spare hours he buys up discounted items such as skis "that people don't really need" in the Midwest, "where it is pretty flat", and sells them online to people in places "where there are more hills". What makes Ben stand out is that, unlike many Ebay users, he will in April voluntarily declare this income to the Internal Revenue Service and pay US business taxes.