What kind of value would a will-o-wisp in a bottle ?

@mikemearls say a player managed to catch a will-o-wisp in a bottle blessed by a god. What kind of value would it have on the black market?

— Jordan Dansereau (@HowlVakarian) June 11, 2016

First, I like your style. Second, I'd say 1d4 * 1000 gp. https://t.co/FOSaZuwFgs

— (((Mike Mearls))) (@mikemearls) June 11, 2016