Im a native enlish speaker and that doesnt make any sense to me.

The question 'What's to pay?' is one i have never really heard [ever] but it seems as though its reffering to what you have been through and such. I am thinking this because 'pay' could be asking about what you have 'payed' or in a sense gone through. Where did you find that dialogue though?

You have either misheard or the first speaker has used an inappropriate idiom. The second speaker interpreted it as I suggest. 'There'll be hell to pay' IS an idiom - perhaps they appropriated it for their own purpose to mean 'what's your news?' - what bills have you racked up, what's to be paid for, what's new?