Cork "base" must be more costly than the others given that crews stay in city centre hotels. I'd imagine the two four star airport hotels would be less expensive. Most of the overseas charter crews stay there.
As far as I know, Cork now has a full cabin crew and pilot base, and therefore crews do not stay in hotels anymore but in their own homes. I think from time to time Dublin pilots overnight in Cork, and they do stay in hotels, but generally everyone else goes home at night.