Even more on the subject  - I got a reply from an adoptive parent that asked for suggestions on how to reply to an adult. Here's my reply:

For the question - "How much did your adoption cost?"

I would use basically the same idea as with the adolescent now just simpler. So here are my thoughts...

How much did your wedding cost? Probably will stop someone annoying in their tracks.
Or you could go the educational route...
How much did/does getting married cost?  Not the optional stuff like the dress, the decore, guests, food, etc.  - the nessasary costs?
Unlike not using wedding planners and caterers which might mean that it coud be easier for things to go wrong like the food gets cold or the flowers aren't the right color... Not using an agency and/or a lawyer in such a complicated legal (2 countries & the UN) process means that things could go seriously wrong and the adoption could fail. That is like a miscarriage-a death. Its heartbreaking. 

"Why is it so complicated?" A minor is involved. 2 countries & the UN trying to do right by a child/children.

For the question of why adoption/why international adoption...
Why did you get married in a church/a hotel/on the beach/....?
Or...
Why does one couple choose to get married in a hometown and another in the city they currently live in instead of someone's hometown?  Everyone has to decide what works best for them - and  socially we say "It's your day - do what makes you happy" because in the end it's all about the love...right? Same for us.

There are lots of ways to become parent's/have kids.  We did what works for our family.

Total deflection for me are these:
No matter how a family chooses to have kids we are happy for them.

Isn't it great that we created more love in the world?
(That one works for lots of questions)

I will say people are mostly kind (we may be lucky but nobody mean/rude yet since we have been home) and I usually feel open and fine with questions because adoption is complicated and people really just don't know. I also don't want to be rude in return.  However there are times when I can't be "ON" and so I try to smile and deflect. 

For me its all about the love - Peace out.J/K!!!

Lisa