What’s the damage?
Definition 1 of 2
Pro Tip 1/3Casual Inquiry
Used informally, when asking about cost in a relaxed or humorous way. 
After eating at the new restaurant, I chuckled and asked my friend, 'what’s the damage?'
Pro Tip 2/3Not Literal
Figurative speech, not about actual physical damage, but related to financial cost. 
She admired her new haircut and asked the stylist, 'what’s the damage?'
Pro Tip 3/3Light-hearted Tone
Often used to lighten the mood when anticipating a high cost or bill. 
Seeing the mechanic's face, he joked, 'So, what’s the damage this time?'