Some months ago my wife's 500C remote key was stolen. She'd gone shopping with a friend and it was taken from her pocket. Fortunately they'd gone there in the friend's car so the thief didn't get the FIAT. FIAT dealer wanted about $600 for a replacement (and several weeks for delivery!) but, as she was planning to trade the car in the near future, we found a reputable locksmiths who supplied, cut and coded a new 'manual' key for about $120 - roughly £65.
She lost the convenience of the remote locking of course...