04 Odyssey Computer

Hi

I am trying to buy a 04 odessey but it was dammaged buy water flood.A freind of mine told me that we are going to change the computer.Does anyone know how much it can cost to get a new computer or get one from a junkyard.is there anything else that we have to do to have the car running.
In fact, I am asking these questions to have an aproximate idea of the overall cost if I was to buy this odyssey.
Thanks,

I wouldn't even waste my time with a flood car to be honest with you. You don't know how much if any water got into the inside wire harnesses. And thats not a headache you want to deal with down the road.