The Xiaomi Mi MIX is priced at ¥3499 ($509) for the 4GB RAM + 128GB version and ¥3999 ($581) for the 6GB+256GB variant irrespective of the color. If you head to Japan, try not to be shocked if you see it being sold for double the price.
In a second-hand store in Tokyo that specializes in importation of devices, the 6GB RAM variant of the Xiaomi Mi MIX was seen selling for 109,800 Yen which is roughly ¥6700 ($974)!
For that amount, you could purchase the 6GB variant and still have enough to buy a Xiaomi Mi 5S or Mi 5s Plus if you buy from Mi.com. However, if you will be buying from third party re-sellers, you might be paying more or less the same amount as the store in Japan. A quick search on one of the major online stores shows that the 4GB RAM variant sells for about $740 (¥5100). That shows how much re-sellers jack up prices for phones like this.
The Xiaomi Mi MIX is a 6.4-inch device with no bezels on three of its sides. It has a Snapdragon 821 processor, a 16MP rear camera and a 5MP sensor up front. It also has NFC, a rear-mounted fingerprint scanner,and a 4400mAh battery with Quick Charge 3.0 support. Although it runs Android 6.0 Marshmallow out of the box, it should get updated to Nougat later.