hi,
i booked a free flight yesterday evening and there were still loads left. somehow, my eco aversion to flying got killed off by the concept of totally free.
usually you have to pay a £4.00 debit card charge. but i have a visa electron which means its free.
also, check details carefully, they try to add in insurance and baggage etc. to make it cost.
but if you do it right its totally free, no airport taxes or anything either.