These base metal semis come from Antioch in Syria with a portrait of Nero on the front and S C enclosed by a laurel wreath on the back. Typically the diameter is about 20 mm and the weight about 7.5 grams.
As requester Classified points out, most of these coins are the 'head right' variety, but there are a few 'head left' coins. In our professional database, a search for 'nero antioch semis' produces a total of 35 hits, with only 2 of the 'head left' variety. The coin in our main picture (upper left) sold for 130 British pounds (about $170 US dollars) during a 2014 auction by Roma Numismatics in London. CoinQuest thanks Roma for use of their coin photo.
Values for the rare variety are higher than the common variety. Very approximately:
worn: $50 US dollars approximate catalog value
average circulated: $100
well preserved: $220
worn: $70 US dollars approximate catalog value
average circulated: $160
well preserved: $320
As with all ancient coins, the prices above are extremely approximate. Each coin stands on its own merits. Coins with full strike, intact legends, and good eye appeal are the most valuable.