Last time I needed truffles, I bought a small jar with 2 or 3 1" specimens from Whole Foods, in some kind of liquid (I don't remember what kind). Look near the cheese department.
It was good enough for truffle deviled eggs, I don't know that I'd try to do an Alinea Black Truffle Explosion with that.
What is patriotism, but the love of good things we ate in our childhood?
-- Lin Yutang