Didn't "the Last Supper" takes place in an inn?
It wouldve been the First Centurey equivalent of the Tastee Diner, or a Denny's. A blue collar greasy spoon.
Any cup used by a customer would be standard issue ware of the time. Not some jewel encrusted goblet custom made for kings ( how its always imagined).
One of the many possible 'holy grails' displayed on some cable show (the History Channel, or something) actually was a rather plain and unadorned ancient looking off white little goblet that looked alot like what I always imagined "the Holy Grail" ( ie the last thing a Judean carpenter wouldve taken a sip from while dinning with his buddies in a greasy spoon) to actually look like. Not that I believe it, nor any extant artifact, is "the Holy Grail". But if there were one thats what it would look like.