[Shopping] The price difference between the Cartier ring in Hong Kong, Macau and the mainland?

Ready to go to Hong Kong and Macau at the end of the year, and take a pair of wedding rings by the way. I do n’t know how much the price difference between Cartier in these three places in the mainland, Hong Kong and Macau? Where to buy the cheapest. For example, what kind of precepts of rose gold happiness?