I'm very excited-- I just discovered that A.S. Pork Store, that little butcher shop on 5th Ave around Carroll Street, makes wonderful sandwiches for take-out. I had "Il Classico" which had prosciutto, movvzarella and tomato.
There's about 30 different combinations on the menu, and they're all $5 to $6.50.
It's about time I found a cheap lunch place in Park Slope. The only drawback-- no seating.