The sign "how much" is a "wh-q" sign. That means since it is a question that starts with the letters "wh" you should furrow your eyebrows a bit.
How-much: (volume) How much salt should I put in?
How much cost or worth?
Use "F" handshapes. The tips of the thumbs and index fingers on each hand move together and touch the tips on the other hand-twice.
How much is that? How much did it cost?
How much cost? (second example-- same sign as above).
As in: "How-much should you tip a waitress?"
Non-Manual Marker (Facial expressions and or body language): "Wh"-facial expression