From HGWiki

Can only be found on Server 111 where he sells Augmenters, up to and including UR quality, for prices that increase every time they are purchased. The Augmenters for sale randomly change on server reset. The sale price next time they appear in the shop drop by one tier from the last purchased price.
Some of the more popular Augmenters can reach 10s (even 100s) of billions of GP in purchase price, if you find these attached to 'junk' items they can be sold to other players who can then strip them off and reuse.

Location

• The Workshop