It's hard to put a price on a sense, but let's say someone had entirely lost their hearing due to illness/accident and was told an operation that would completely restore it would cost £50,000. That price would probably be seen as a very good alternative to being completely deaf for the rest of their life.
But how many people would fork out/raise money to pay for ear plugs costing £50,000? Not many I'd expect, especially if a cheaper alternative was available.
So the blanket, "How much is your hearing worth?" statement seems a bit rediculous to me.