My opinion? Personally, I'd go to your local John Deere dealership and see what they would give you on a straight sale. See what they think a reasonable offer is, and then make your decision from there.
Asking any forum what the value of a John Deere, or any other brand of tractor for that matter, is worth will get you no where, as you will usually get three different answers. One answer from a collector, will be a high number, as that is what he hopes his tractor, like the one you are asking about, will be worth if he should try to sell it. Another answer from a collector, will be a low number, as he is looking for the same tractor for his collection, and hopes that he will obtain the tractor that you are looking at, if you decide that you aren't interested in it. And finally a third answer, from someone who isn't a collector, but is making an estimated guess, as he just wants to sound like he knows what he's talking about, and wants to fit in. And before I get any nasty PM's or comments, I'm not referring to any of the above replies!
These little lawn tractors can be found, and are not considered "rare". They are nice, don't get me wrong, but they aren't worth the money that guys are asking for them. You used to be able to buy these tractors for $50.00 or less about 5-7 years ago when no one wanted them. But now all of a sudden, people started collecting them due to not being able to afford to buy the bigger tractors anymore. Why? What is making these tractors so expensive? Inflation? Price of steel? No. Because John down the street was able to sell his $50.00 tractor for $100.00. Then Tom on the other side of the street, saw what John got for his tractor, and decided to sell his same tractor for $150.00. Tony on the other block, heard from John that Tom just sold his tractor for $150.00, so Tony decided to sell his exact same tractor for $300.00. Meanwhile, John just bought another tractor like he just sold, for $25.00, and decided to flip it right away, and tried to get a little more that what Tony sold his for, and put an asking price of $500.00 on it. John sold the tractor within a weeks time. So what's the blame? I think it should be who's the blame, and the answer is us! We are the blame. I believe in making money or turning a profit, but I don't believe in screwing someone out of their hard earned money. As long as we are dumb enough to pay these ridiculous prices for tractors that aren't made of gold, then we have no right to complain about how much we spent on a tractor, or how outrageous the seller is with his asking price on Craigslist or Ebay.
If the price jacking don't soon end, collecting won't be fun anymore, because you won't be able to afford the hobby.
Just me two cents worth, and again, no finger pointing to anyone in particular.