I've had a number of Oakleys, most of them can be found for much less than retail on Ebay, you just have to make sure you buy from a reputable seller. A normally $275 pair of Julets, for example, should go for around $200 on Ebay.
Most Oakleys are pretty sturdy, and can be "freshened" by the factory for minimal cost, as long as they are not obviously abused. The major caveat here is that the coating on any of the colored lenses, like the fire iridium or ice blue, is pretty damn fragile, they will scratch if you wipe them with anything but a very clean microfiber cloth. I'm pretty sure Oakley won't replace scratched lenses under warranty.
So, bottom line, they are very good glasses, very stylish and well made, but you have to be extremely careful with the lenses. If you are one of those people who toss your glasses around, or are constantly dropping them, then Oakleys are probably not for you.