At $1,000, a full Valve Index kit is on the higher end of the price range for PC virtual reality hardware. Nevertheless, in the wake of the Half-Life: Alyx reveal it looks like Valve is moving kits at a fast rate—if you place an order in the U.S. now, Valve can't guarantee you'll receive it before Christmas.
Road to VR has been keeping an eye on the availability of the Index in recent days and spotted the new backorder warnings on Valve's store page. At the moment, the only option to buy Index-specific hardware from Valve is to place an order for the complete kit. The headset, controllers, and headset/controller bundles (which can be used with compatible Vive accessories) are unavailable for purchase.
Index availability in Canada, which Valve only added to the list of supported countries with the announcement of Half-Life: Alyx, is currently subject to the same limits. The full list of countries the Index is available in can be found here.
The Index isn't the only way to experience Half-Life: Alyx. Though it'll be exclusive to VR, Valve has designed the game to work with SteamVR-compatible systems including Windows Mixed Reality headsets, HTC Vive hardware, and even the Oculus Quest via the newly-added Link functionality. Still, owners of Index hardware will receive Half-Life: Alyx for free.
While Half-Life: Alyx is almost certainly helping drive demand for Index hardware, as we draw closer to the holidays we may see other VR hardware go on backorder too. Bundles for the Oculus Quest sold through Facebook's storefront are currently set to ship in the U.S. between December 13–17. That leaves plenty of time to get ready for the March 2020 release of Half-Life: Alyx, but if a holiday break with VR is your aim, then your options are starting to get slim.