Have you ever not known how much your bag costs? Whenever I book a ticket, it usually says how much a bag costs, and there is a link to the extensive rules of what can go in.
But when you search for a ticket do you get to select how many bags you are checking? That is the key to having this issue settled correctly by the market.
Never been on an airline that charges for overhead bags. I would guess Ryan Air does that by reputation but never heard of a US airline doing that. Just checked out google flights and there is it.
