I had read about this place on happycow and stopped in while walking around in the Castro District, October 2012. Here's my Frapez review.
It's a little smoothies and fresh juice bar that emphasizes on health and also sells several bulk bins items for takeaway (almonds, cashew, goji berries, energy shots). You can customize a juice with the produce that they have. There is also a small food menu that includes salads and wraps.
I got a custom juice with carrot, ginger, celery, and spinach, and it was tasty and inexpensive. A good stop for a juice or smoothie, grab and go or sit at one of the few small tables inside.