I did a group buy on them last time. I got them from the Vacaville Costco. The reason why they were so cheap is because it included a PG&E rebate. When I was there a few weeks ago, they still had a pallet full. I would offer to buy some more, but I don't think I will be heading back out to that Costco until Saturday/Sunday (after the meeting).
Xia - if your bulb is dying out, please bring it back to me and I will swap it out for you. I can always do an exchange at Costco.
Minh