Trading on eBay

'The World's Online Marketplace' has one million registered users in the UK alone so there's bound to be someone who'll pay for anything you have to sell. Start with stuff you don't want (old CDs, clothes, toys) to get a feel for it.

Average pay: the sky's the limit - but unless you're selling something rare or valuable, don't expect to make a fortune.
More info: go to eBay and click on 'eBay explained'.