1) "Too expensive compared to what?"
"Expensive" is a relative term. If you can find out what the prospect is comparing your product or service to, you can more precisely differentiate value.
2) "Really? How are you coming to the conclusion [product] is too expensive?"
This prompts the prospect to break down their reasoning. Once a salesperson better understands the specific concerns behind the sticker shock, they can more easily address them.
3) "Are there some boxes we left unchecked?"
Circle back and make sure the sales process unfolded to both parties' expectations.