What a difference a year makes. This time last year, virtual reality (VR) was the stuff of science-fiction stories and clunky developer prototypes. Today, the market is virtually flooded with inexpensive smartphone-based VR headsets that let ordinary people try this emerging tech for about the price of a good meal. And there's not one but two high-end VR head-mounted displays vying for your hard-earned money in 2016. Truly, this is the year that you should start to understand VR.

Fun with your phone

You don't need to spend a fortune to dabble in the world of virtual reality. Google Cardboard — a headset literally made out of cardboard — can be had from any number of online sellers for $30 or less, routing a split screen 3-D view to your eyes not entirely unlike an old-fashioned View-Master.

And if you prefer a headset that doesn't disintegrate when wet, a number of companies have built on the idea of Google Cardboard with quality plastic frames. Homido and Merge VR, for example, work with both iOS and Android phones to deliver surprisingly good virtual reality experiences, using games and simulations, for under $100. Heck, there's even a View-Master brand VR headset.

But perhaps the most elegant headset in this category is the Gear VR, which works only with late model Samsung Galaxy phones, but includes an integrated virtual reality app hub. And the superb graphics are second only to what you’ll find through the lens of the Oculus Rift or HTC Vive.

Tethered headsets are around the corner

A woman tests the HTC Vive at the Mobile World Congress convention The HTC Vive, while attached to a computer, is intended to allow the user to walk around and 'experience' the virtual environment by moving in the physical space. (Photo: Joseph Lago/AFP/Getty Images)

Speaking of which, the big guns are arriving. Oculus Rift — a $600 headset that gained notoriety as a record-setting Kickstarter and then later when Facebook paid $2 billion to purchase the company — finally started shipping to customers in late March to generally very positive reviews. The Vive will be shipping this summer for $800.

Both of these headsets connect to your PC and require a lot of horsepower, such as an NVIDIA GeForce GTX 970 graphics card and an Intel i5-4590 processor. Both use external room sensors to know the precise position and orientation of the headset in 3-D space. If you're looking at a virtual train set on a virtual table, for example, you can lean in, peer straight down and look around corners, while the image in the headset shows you exactly what you'd expect.

But there are key differences. Oculus Rift is designed to deliver a "seated experience" — it doesn't know anything about the geometry of the room you're in. Vive, on the other hand, lets you move around the room like a "Star Trek" holodeck made real. And it even has forward-facing cameras that can combine the real and the virtual into a single visual experience, so you aren't blind while wearing them.

Content (as always) is king

Of course, none of this matters if the software doesn't provide a compelling experience. In the same way that early cinema wasn't very interesting until cinematographers figured out how to really take advantage of the technology, the quality of VR games and simulations will no doubt evolve radically over the next few years.

But even right now, there's some shockingly good content. "Smash Hit" (video above) moves you through a surrealistic world made of glass in which your only goal is to break things with a supply of metal balls. It's visually stunning and absolutely mesmerizing. Meanwhile, "Gunjack" and "Eve:Valkyrie" put you in breathtakingly gorgeous outer space shooters.

Both Vive and Rift come with a small assortment of bundled games so you have something to do as soon as it's plugged in, and an impressive array of games are arriving over the course of 2016. For example, 20th Century Fox has been privately showing a game based on the Matt Damon film "The Martian," and some of its sequences, such as when you're driving a rover around the Martian surface or floating in zero-gravity, are stunning.

https://www.youtube.com/watch?v=GwzAYXl8ilc&feature;=youtu.be&t;=2m30s

When you realize these games represent the first wave of virtual reality entertainment, it makes you wonder what we'll be doing with our VR headsets in the year 2020.