You may not have $3,000 to spend on the Microsoft HoloLens Development Edition, but that doesn't mean you can't learn how to make apps for the augmented reality headset. Microsoft has just posted a ton of tutorial videos showing many of app development features for the HoloLens.
The videos show the basics of how to create an app for HoloLens that takes advantage of its features, such as spatial mapping, which allows 3D objects and characters to interact with real-world items. There are also tutorials on how to use spatial sound in HoloLens apps, along with gesture and gaze input features. Microsoft is expected to start shipping the first units of the HoloLens Developer Edition on March 30.
Source: Microsoft HoloLens (YouTube)