Really, it is good for you to opt for Celine sunglasses. You should know that Celine is a brand founded by Celine Vipiana in Paris decades ago. Initially they focused on making shoes for kids. But nowadays their products especially sunglasses are widely appreciated for their wonderful design and quality. You should prepare about 400 to 600 dollars. If you want to get them at cheaper prices, just try to search through the web.
I just search it online and find several sites provide celine sunglasses. And i just check them, their prices are different from each pair. You can get the cheapest celine sunglasses over 200 USD. And there are some of them priced Over 300 USD. So, how much you cost on it depend on what type of celine sunglasses you choose. Here the sites: http://www.rockdish.com/. Good luck.
I think you'd better prepare about $500 which could allow you to choose any kind of celine sunglasses that you have a favor on. If you want to buy at cheaper price, you could go to the online stores to have a look, such as the ebay and amazon to have a look.