The bags are due to sell for just 1p. But by the time you add VAT, surcharges, P&P and the £7.50 credit card surcharge then they will be about £40.00
You forgot insurance ! if they are being sold off the website and not by a shop in Stansted, at least the sales personal won't slam the door shut at 18:30 and one second.....
There is an amazing choice of carry-on luggage these days and frankly I think paying more than 15 euros/15 quid isn't worth it. I've seen squishy bags with wheels and pull-out handles for this price.....
R