If it's someone who rides and is in the market for a new bike, I'm pretty honest and tell them what it cost.
If it's someone who doesn't ride and is curious. I just say, "it was pretty expensive". And then they can guess if they want, and I'll say higher or lower. It ends there.
I'm not really offended by money talk like other people can be... so it doesn't phase me when they ask.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"