Hi there, I'm trying to figure out the value of this watch. It is posted by an online seller and lists it as a no-name Unitas movement watch from the '30s. 31 mm case w/o crown. The listed price seems optimistic and I'm interested in offering a fair market value for this piece. I'm fairly new to the watch trading game, so not terribly sure how to approach this. I realize the the value is the price that any one person is willing to pay, so a ballpark is what I'm looking for, if that can be estimated.