Not everyone is willing to commit to the high price tags of the Oculus Rift or PlayStation VR or HTC Vive.

If you consider yourself among that cautious crowd, you'll be glad to learn there are other, affordable VR headsets available. In fact, these alternatives function just like Google Cardboard and work with Cardboard apps and games. That's because they are certified Cardboard viewers.

With a viewer, you can experience virtual reality for less than $100 (or, more often than not, less than $30). All you need is an Android or iOS smartphone. We explain everything you need to know about these Cardboard rivals below, including basic information about the original Cardboard viewer, its apps and games, as well as which cheap viewer you should buy/build for yourself.

Google Cardboard is a do-it-yourself cardboard kit that Google introduced in 2014 but only recently began directly selling via the Google Play Store. You can buy it for $15 and then assemble it to end up with a virtual-reality headset. It's technically considered a simple viewer - because it's not a standalone device that's ready to work from the get-go. It requires an Android or iOS smartphone for a display and processing power.

You can learn more about how Cardboard works from Pocket-lint's reviews:

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Once you get a Cardboard kit, then fold it, and slot in your phone, you can explore a variety of Cardboard apps and games. These experiences, which are designed to work with any Cardboard-certified viewer, are available in Google Play Store or Apple's App Store. You can also try basic VR demos free of charge via the Google Cardboard app for Android and iOS. The Cardboard app also lets you manage Cardboard settings.

Here are some of the best Cardboard apps and games out right now:

Google launched a "Works with Google Cardboard" certification program that allows manufacturers to submit prototypes of their Cardboard-like viewers to Google for review. If those prototypes meet Google's specific standards, which are outlined here, the company will certify the final product. Certifications helps the viewer get traction by letting users know that it works with Cardboard apps and games.

You can learn more about the WWGC program from here:

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The best Cardboard rivals are viewers that have been certified under the Works with Google Cardboard program, because they not only function just like Google Cardboard does but also work with Cardboard’s full range of available VR apps.

Here are some Cardboard rivals out right now:

There's three things you should consider before buying a Cardboard-like viewer: price, materials, and the size of your phone.

Price: The cheapest headsets, which cost the same as Google Cardboard, are the Goggle Tech C1-Glass, V2, UC 2.0, and Homido Mini, while the most expensive headsets are the VR One Gx and SmartVR. There are of course a handful in the middle-price range, including the View-Master, Knox V2, Powis Viewr, P2, Pop 2.0, and Dscvr. We'd recommend sticking to the low-to-mid range if this is your first go-around with VR.

Materials: The Knox V2, Powis Viewr, P2, and Pop! 2.0 are all made from cardboard, so if you're looking to get a near-exact experience to Cardboard, these viewers are your best bet. If you want to go a step up and take the plastic route, consider the View-Master VR and Dscvr. The View-Master VR is a modern take on the classic toy that Mattel made for years, so this option might be especially ideal for kids.

Phone size: Choose a viewer that fits your phone's screen size. Most Cardboard apps work with Android 4.1+ and the latest iOS smartphones. From what we can see, Dscvr works with phones ranging from 4 to 7 inches, while Mattel's offering only works with phones from 5 to 5.99 inches however, so be sure to check each viewer’s website for more details and specifications.

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You could always order an extra large pizza box and build your own Cardboard-like viewer, though you will also need to get ahold of lenses, magnets, velcro, and a rubber band. If you're all set, download instructions from here, or check out Pocket-lint's guide below:

Check out Google's Get Cardboard site for more information.