Can Wishing Ring be sold after using it?
 

Is it true that items may only be sold from play and not from your hand?

After using Wishing Ring once, can I continue to carry it and sell it at a later time?

Re: Can Wishing Ring be sold after using it?
 

No. A usable once only item can only be used once. After it's used, you discard it. However, the rules state that you can sell Items from your hand and from in play.