I've been asked by a couple of people - basically quite dodgy-looking men, and I didn't tell them, as I suspected that they might at some future point try to steal the dog (not difficult to see someone's patterns on a local common over a few days). Normal strangers would just not ask. Some of my friends and family probably asked, out of interest (as in, how much does a puppy cost these days), but strangers - nah! Soooo not appropriate
If anyone asks again I'll tell them that he was pretty cheap as he has all sorts of health issues so really expensive vets bills (hopefully won't be jinxing my baby's health, but will put off anyone who's thinking of half-inching him!). There has been a dog-theft near me recently, so I think my paranoia is justified.
So I don't think you over-reacted by feeling pissed off with this woman's question.