Well, generally speaking, the prices of this kind of sunglasses are kind of high, especially when you get them from the official stores. So I will suggest you buy them on online shop. For example, you can buy them at http://clothing-and-accessories.become.com/jimmy-choo-anouk-shield-sunglasses-black--compare-prices--sc1503312739. In this place, they can provide you many different kinds of products what you like and you can just pick one pair depending on your own needs. For example, you just need pay about 350 dollars to buy them. Also, you can buy them spray which can be good to protect your sunglasses. Besides, you should know that they are UV protected, so that they can shield your eyes from the bright sunshine and avoid the UV rays. Anyway, you can jus have a try.
As far as i could know that Jimmy Choo's sunglasses are sold at Nordstrom stores. And their prices are different from different style of Jimmy Choo's sunglasses. And most of them are ranges from $295 and 395. It is a little bit expensive for me. Here is a websites provide Jimmy Choo's sunglasses, you can have a look: http://www.jimmychoo.com/sunglasses/icat/sunglassesuk
The average price of Jimmy Choo sunglasses is about $270 which should be a little expensive. If you buy it from the online store, you will save a lot of money than buying it in the real store. The design of it will attract you because of the special style. And the quality is so durable too. You could base on your favor to choose one.