Yes, I have just bought the porsche sunglasses from the http://www.smartbuyglasses.com/designer-eyeglasses/Porsche-Design/ for about $300. There are many other types with good quality and excellent designs. You could go to there and have a look. The price is suitable which will absolutely cheaper than those in the real stores. But the quality is just as same as those in the real stores.
You should know that Porsche is one of the most renowned brand in the world, producing a wide range of products, including designer sunglasses. As a matter of fact, their sunglasses are extremely pricey in the sunglasses circle, a pair of them could charge you as much as 600 dollars, which discriminate them from the rest brands. But I think they are worth buying since their quality and design are exceptional.