False--price is largely dictated by what new users (who can't afford to buy a new device) are willing to pay, not what the seller (who used the device) wants.
(Nitpick: I think there's a difference between "False--" and "FALSE!".) Regardless, though, it may be on the blunter side, but I think it's a better choice than, "I'm sorry, good sir, but in my humble opinion you are perhaps less than correct."
To the OP--I'm sorry if I came off as impolite, I truly was aiming for conciseness, not malice.