As others have said the old smaller combines can be had cheap. There are even combine demolition derbies held with them!
I would have to second fwj's suggestion that you consider finding someone that does custom work. It may become very frustrating for you to keep an old combine running and it would cost you a fortune to have a dealer work on it for you.
However, if you are very mechanically enclined and up for an adventure then by all means have at it. It's hard to match the satisfaction you feel when you see the grain you grew coming out of the auger and filling the hopper.
I would have to second fwj's suggestion that you consider finding someone that does custom work. It may become very frustrating for you to keep an old combine running and it would cost you a fortune to have a dealer work on it for you.
However, if you are very mechanically enclined and up for an adventure then by all means have at it. It's hard to match the satisfaction you feel when you see the grain you grew coming out of the auger and filling the hopper.