To clarify if there is any confusion. The bribe amount is not deducted until the fights happen, this gives you the chance to change up your challenges and avoids and bribe amounts anytime you like up until when the fights happen. If your stable doesn't have enough gold on hand (i.e. not in the bank) when fights happen your bribes will not be valid. If you made multiple bribes but don't have enough to cover them all, some will be valid, and some will not. It'll depend on the order that Jimmy negotiates with the arena officials. You'll want to make sure you have more gold on hand than the exact amount to cover your bribes if you still have gladiators in the lower brackets as you could lose gold via the spoils of war which could then leave you without enough gold to cover your bribes come fight time.

Good luck in the Pit!

-Nate-