I guess I never got the taboo about discussing money. I never ask the question, because I truly don't care what something costs, unless I am buying one, in which case I will figure that out myself. I don't get terribly offended when someone asks - I just don't get why anyone would care.
Let me tell you a story....
When I went to high school, I could never see why people would spend $X for a pair of Levis (the hot jeans at the time), versus $1/4X for a pair of GWGs. So, I bought the cheap jeans, that were just as good and fit just as well.
Many years later, I was talking to my brother about how "those kids today" are so wrapped up in designer labels. I said that I wore my GWGs proudly, and no one thought less of me for it.
My brother smiled sadly, and explained to me that yes, they did. I just didn't realize it. This explained a
lot about my teenage social life, I'm afraid.
So, YOU may not care about what the price of your home, car, or clothes says about your social status. But unfortunately, many people do. So, asking "How much did that cost you?" is a coded way of asking "Are you a winner or a loser?" And many people object to clarifying that to satisfy someone else's curiousity.