Square baler maintenance cost

Hello everyone I have a question about square baler maintenance. I've been looking at purchasing a square baler. Iv found a real nice JD 336 that an old farmer has on Craigslist. He has owned it for 14 years and looks like he's taking real good care of it. I really don't know much about small square balers yet so if I bought this baler and took it to a dealer what would I expect to pay to have it checked over and fine tuned minus the cost of any parts if it were to need them? I'm sure some of you do this in the fall or spring just looking for a ball park estimate before I make an offer. The guy said he had it to the dealer about 4 years ago to have the knottors worked on and plunger shims adjusted. He seems real honest and says it's been real reliable for him with out and issues.

Thanks guys.

Square baler maintenance cost