This is yet to be officially confirmed by Microsoft, but we have unofficial confirmation that anyone who orders a Lumia 950* or Lumia 950 XL before January 31st 2016 will be eligible to receive a Microsoft Display Dock (approx. $99 value) for free.
Owners getting vouchers to order it themselves for free from Microsoft is the most likely option, we reckon.
Certain retailers let slip this information on the day the two Continuum-enabled Windows 10 smartphones went on sale, only to retract it later the same day, as Microsoft (for whatever reason) wasn’t ready to announce it yet.
Microsoft will not be able to make the HD 500 Display Dock available before or at launch of the Lumia 950* and Lumia 950 XL, but will distribute them to Lumia 950 owners as soon as they become available.
Exactly how the Display Dock will be distributed is yet to be confirmed, but it will either be done via the retailers or directly by Microsoft. Vouchers to order it for free from Microsoft directly is the most likely option, we reckon.
* Update: The display dock may be distributed by ordering it through a pre-installed app on the phone(s). We now also have some conflicting retailer-sourced information, which makes it unclear whether the Display Dock will be free only for the 950 XL or both. We will try our best to get official word on this and keep you posted. Our thanks to leonmeijer for contributing in the comments section below!
The Microsoft HD 500 Display Dock features one of each Display Port, HDMI and USB-C connectors, as well as three (3) USB ports for connecting peripherals like keyboard, mouse and external storage devices.