Those are actually H1 bulbs on the link, but eBay is a source for some imported bulbs, the only downside is the additional shipping cost.
You can get H4 Osram Silverstars +50%'s at powerbulbs.com at the current exchange rate price of US$27.95 for a pair and shipping is free.
Autolamps-online.com also has the H4 GE Megalight +60% for $27.99 a pair, and is having a "buy one pair, get a second pair at 50% off" promotion. Shipping is free.
For $11 though, the Sylvania XtraVisions might be the best choice for a replacement bulb for most US DOT-spec headlamps, both in price and performance.