Beautiful work. Whoever was in charge of the auction should know better than to let a piece like that go for $150...or stop auctioning the work of others. At the very least s/he should have asked you for a reserve number, minimum, to start the bidding. If it didn't sell, well, you could donate it or do what you thing appropriate. The decision should always rest with the artist. Sorry about this, for you. This is obviously done with love and you gave it a lot of thought.