I bought 2 of them on a huge auction site that shall not be named. The only problem with Oust fans is that you really need to clean them and let them air out for about a week at least before using them in your humis, because when the come the plastic is pretty much infused with whatever fragrance it was packaged with (due to slight leakage I assume).
I had to rub mine down with ammonia twice and let them air out for a long time before I was convinced they were no longer smelly.
By the way, I LOVE my Oust fans! Reminds me, I should get another one...