The Spitting Eagle "variety" isn't a die variety at all...it's a die clash that happens once in a while on various dates. When anyone can assign a name to something and it sticks, there's always someone who will have to have one. The TPGs recognize it (for a price), but you won't find it in the Cherrypickers' Guide. As far as value, find the right person and the sky is the limit!
Spitting Eagles are one of those minor errors that people hype in order to make it appear rare and valuable. First of all, most spitting eagles are real errors, as previously mentioned. The spitting part is the remnant of a clashed die. However, it is a minor error and most knowledgeable and experienced error collectors know this. Since there really isn't a strong collector Base seeking to purchase minor clashed dies, your best bet would check eBay SOLD listings (not listing prices). This will give you an idea of what novice collectors are paying. If you wanted to sell it, my guess is eBay would be the way to go. Error dealers wouldn't be interested Still a cool (although minor) coin. Nice find