RE: Is This Worth 600??
Often in more instances than not, people want to try and squeeze out as much as they can out of people via their asking price. After browsing around eBay a little bit, the maximum price posted on their is 525 BIN so there's really no way this guy should get $600 unless somebody happens to give that to him. I would say that Ofna would be worth about maybe $400 tops, but I am almost certain that $600 is a very high price.
The value of R/C's diminish greatly once they obtain a "used" title. Unfortunately, that is the nature of the hobby, I've sold my stuff off numerous times and the profit amounts to nowhere close to what you spent, just a fact of the hobby we (and everybody else selling) have to accept.