If you want to buy the celebrity sunglasses, you will have to go to the real store of the eyeglasses to have a look. You will have to pay a lot of price. You could also go to the amazon or ebay to have a look. The price there may be suitable. And the design of the sunglasses is similar. You could go and have a look.
Vanessa has worn lots of sunglasses, I just know a pair of them. The sunglasses are produced by Rubber Duck, it may cost you $50, not too expensive. The color is purple, and the frame is quite classic.
You can go to the shopping mall, shop at their real store, and the shop assistant must know what you want to buy.
Then you can visit Rubber Duck's official website, they sell sunglasses on the web.
By the way, ebay and amazon would also be helpful. You can type "Vanessa Hudgens sunglasses " in the search bar, you can find more than one type of the sunglasses she has worn.
Ok, I can see that you are quite interested in the type of sunglasses vanessa hudgens chooses. Anyway, those sunglasses are quite suitable for females and could make them appear cuter. You could actually see those stella maccartney sunglasses over Walmart or some large shopping center, where the prices could be more acceptable. Or you might as well contact their customer service department for help.