'Sounds like a "tire kicker" to me. You know the type, all blow, wannabe bigshot. 'Eager to impress you with his money and to imply that you're not worth it.
Stick to your guns. In fact, if he does shop around and come back to you, go up in price. You're still not getting what it's really worth.
"That's my advice and I'm stickin' to it."
Karen