Mike- the eBay buy it now price $4,600 is a steep one, probably double what it would get on an open auction, but, this said that toy is in remarkable, original condition {for something 80 years old} and the best one I have seen.
It is the largest cast iron toy aircraft ever made
Why not make an offer. I would think something around $2,000- 2,500 would be realistic. You never know.
While an iconic toy and considered rare, they do appear fairly often on liveauctioneers
Here is a summary of recent sales there {add on the buyers premium - like 20% or so.}
http://www.liveauctioneers.com/search?q ... te&rows=20