Two things here: a) it gonna cost you more than 20k, at least couple hundreds. b) if your intention is to use it as a part of 5 piece set it's completely useless, the 12 player buff will only work for you, other members will see it as "health increased by 0" when you switch to a primary bar. There are actually a few threads here regarding this bug, but ZOS seem to do their best in ignoring this problem.

As is now, the best way to implement ebon set in a build is to use jewelry + chest + legs along with crafted Armor Master/Hist Bark/Tava's Favor for weapon, shield and other pieces.