If you are not even seeing any light before it trips the breaker, I'd say the main control board - Control Board MFS-WF206L-00 - is the suspect because it has the power supply for the rest of the circuitry, and that power supply is likely bad. Could be water damage, could be a blown capacitor or a transistor in the high voltage part of the circuit - hard to tell without seeing the part and if there's any visible damage.
As far as costs, RepairClinic sells it for $123.65 but it's out of stock: