Lots of places do. But the cheapest I've found was:
http://www.canadianmarineaquariumsup...cat=341&page=1
If you don't mind shipping from the States, Premium Aquatics ships by USPS.
http://www.premiumaquatics.com/Merch...ry_Code=Hbulbs
Ocean Encounter was $3 US cheaper but they didn't respond to my emails.
Shipping MH bulbs is always a risk. I hope VISA will insure my purchase since shipping companies don't.