You may or may not have a problem finding exactly what you want. IF you are looking for a true Winecock, then you would be seeking a Bronze Winecock that was driven into the Bung Hole of a Wine Cask. Those would be almost impossible to find, and are not a normal part for a Hobbyist. I would imagine that Winecocks might be available to a Winemaking Business that makes much more wine than a guy at home does.
However, I did a quick search in Google. I typed in " Wine Making Supplies " and many, many hits came up. Within the first 5 hits, was a winemaking supply site that offers "Spigots". Those "Spigots" are made of plastic and are usually for use on a primary fermentation vessel and are readily available for around $2 plus shipping.
I would guess that if you have a wine hobby store close to you, they might stock the spigots or would be able to get them for you. Or you could order some on-line, if they seem to fit what you are trying to tap off.