The 8500btu (2.5kw) bedroom on csts around 70p an hr, but once cooled to the required temp it cycles on off making it cheaper providing you keep door and windows closed. I set a temp I’m comfortable with say 19.5c rather than turning it right down to 16-18c whitch makes it cheaper in the long run.
For me its worth its weight in gold and for how often its on during high temps its not that expensive. It will also heat the room but I dont use that.
The lounge one costs slightly more to run as its a bigger unit but they are never both on together or at most overlap an hour before bed.