(Photo via Streetreasure's shop on Etsy)

How much is a 100-year-old subway sign worth? A seller on Etsy has got one listed for $150,000. The sign is a simple black and white design, with the words "Times Square" on it. The seller, Scott Stein (a.k.a. Streetreasure) says the piece measures 8' x 11", and was made by the Baltimore Enamel Company on Fifth Avenue.

He told us, "I acquired this sign at The New York Americana Pier Show almost 20 years ago [and] have been collecting and selling vintage signage for even longer as a hobby. There is no paperwork with this piece—as with most of all old New York street and subways signs they were scrapped or kept by workers who later sold them off."

The Baltimore Enamel Company, which manufactured the sign, "was one of the oldest producers of Porcelain enamel signs in America. They started with license plates in 1903," Stein says. He added that his asking price was determined by factoring in "the rarity of this item and its World Famous Location factor."

Six years ago, someone posted the same (or a similar) sign on Collectors Weekly, noting that they purchased it at the Antiques/Americana Show in Manhattan in 2011, but were uncertain of how old it was.

We've reached out to the Transit Museum to see if they could confirm its authenticity and worth. We'll update if we hear back. But if you're a history buff on a budget, note that over on the MTA's site, you can buy authentic items like a subway seat ($500) and grabholds for a bargain at 25 bucks!