Caught this on the side of a taxi the other day. BarterCard.

‘Bartercard has taken the age old concept of barter and added flexibility, security, accountability, confidence and a 100% satisfaction and results guarantee. Acting as a third party record keeper, Bartercard uses credit units called Trade Pounds to monitor the value of transactions.Bartercard members are issued with a plastic card and trade amongst themselves in a sophisticated fully-computerised barter system.

Fascinating!