The normal cost of the London Evening Standard is 50p per copy. A few months ago they introduced the Eros Card which enables you to pre-pay for copies which can reduce the price to around 33p per copy.
They have now introduced a "London City Airport Eros Card" which gives certain discounts at City Airport but also enable you to buy a copy of the Evening Standard anywhere in London where the card readers are located - not just City Airport - each day at a price of £3 per month (payable by Direct Debit only). This works out at around 14p per copy !
A 72% saving on the normal price ! Can't seem to see any catch with this.