Ebay can be a very reliable place to purchase items. I've bought several items through Ebay, the most expensive totalling around $500. I also bought a set of xenon bulbs and were quite happy. Happy enough to buy another set. If you do decide to buy on Ebay, make sure you read the item description very carefully. Most of the bulbs listed on there are 80/85W, 80/100W, or higher. That's where the "high intensity" comes from. All the blue tint does is give you car an HID look. Also, keep in mind that stock bulbs are 45/65W. I was able to run 80/100W without any noticeable damage to the lens or wiring.

If you're wary about buying through Ebay, Sylvania and GE makes blue tinted bulbs that can be purchased at any auto store.