Ted, you are right, you can't give them a price without any info about the home. Sort of like calling a car dealer and asking "how much is a car?".
For me, the easiest way to avoid the price shoppers is to clearly post prices and options in my brochure and on my web site.
I also use an answering service and I don't have to talk to any of the clients until the contract is signed and I see them at the inspection.