Pandemic: On the Brink Expansion is back in stock at zmangames. No discounted price but it seems to be a difficult expansion to get your hands on. Seems to always be out of print. Prices are regularly marked up on eBay due to demand.
The game is at retail price $34.99 and you have to pay for shipping. But for those of is waiting months to years to get this, it is now finally available.