Well, you should know that Mont Blanc is a German pen manufacture, however, with the passage of time, it began to involve making sunglasses and some other stuff. So, generally speaking, their quality sunglasses will cost you about several hundred dollars, let's say 600 or more. Since their design is so elegant and impressive , they are rather expensive. You can get them through the Internet, e-commerce websites or physical stores.
It seems cool for people wearing mont blanc sunglasses. Personally, i prefer to buy things from internet. And i just search it online. And i find a sites which provide mont blanc sunglasses. But i think the prices of the sunglasses are not cheap. Most of them are sold about $300. So, have your already for the sunglasses? Here is the websites: https://www.opticsplanet.com/montblanc-brand.html
If you want to buy the mont blanc sunglasses, you could go to the online stores to have a look because the price there is cheap. The average price of mont blanc sunglasses is about $300. You could go to the https://www.otticanet.it/mont-blanc.cfm to have a look. Or else, you could go to the ebay to have a search.