Heard this on the news

I heard this on the news a couple of weeks ago and it's been on my mind ever since. There's a guy who wanted a house so he decided to get online and trade a paperclip for a house! Sounds crazy but it might actually work!

He started out by trading a red paperclip for a fish shaped pen (I have one of those!!!) and now in 9 months he's up to a year's free rent on a condo. Now what could I start with and where would I advertise it?