RE: Subway shop revenue?
As with any national chain, sales figures will vary widely. I have seen Subways for sale with annual sales of less than $150,000. Subways product costs are high because of the "pre-prepared" nature of their sandwich fixins. They take a hefty royalty of your top line sales and they will not give you a protected territory.
Always get a list of current & former franchisees and contact as many as you can. Some will give you sales figures, but remember, some will also "fib" a little bit about how they are doing.