I would reccommend against buying eyeglasses online, I can't imagine that they could possibly get them to fit you properly. Whenever I get new glasses, it takes at least 20 minutes for the optician to get them to fit my face properly, because the adjustments must be made in small increments, and one adjustment can throw something else a little out of whack. I assume that you know your prescription, otherwise, how could the online retailer know how the lenses should be ground? Finally $300!?, my pair of titanium flex metal glasses cost $192, and I only had to pay for ~$100 of that because my insurance picked up the rest, maybe you shoud look around for a better insurance carrier as well.
Zenmervolt