Sell How much is Green Cas Cobble worth?

So how much is a Green Cas Cobble worth? I got one (from Odie's giveaway) and just want to know how much its worth before i try actually selling it

 

its varies greatly id recomend making an auction and letting people gamble on it

 

Didn't odie list the values of each item on his giveaway post?

 

yeah but they said the number listed was an estimate and may not be accurate

I was thinking about doing this, it seems like the best course of action if the price varies