You don't have to pay a dime to play Fortnite, the incredibly popular first-person shooter that mixes in a few fort-building mechanics. It's a combination of the game Overwatch and Minecraft, but it has one  peculiar difference. Anyone can download the game from a PC, console, or mobile device and start playing, for weeks or months, without paying a fee.

It's not an unusual premise. Free-to-play games on the iPad and on Facebook are common, but you typically run into a brick wall (figuratively, depending on the game). To open additional maps, unlock the best weapons or to proceed further into the game you have to pony up some serious cash each month, which adds up. Fortnite is totally free--the developer Epic Games makes money when people purchase purely cosmetic upgrades--and that business model is one you might want to consider for your company.

Why does it work? At last count, Epic revealed there are 45 million people who signed up to play Fortnite, which makes it a phenomenal success and a cultural touchstone. What's perhaps even more important to note is that the game amassed that user count in only a few short months since they released the survival version called Battle Royale.

Gaining traction with any app is one of the great challenges of the digital age. There's a lot of app noise, and if you make anything that is even remotely similar to another mobile app--say, anything to do with messaging, productivity, gaming--you'll suffer.

Free has many forms, of course. Toms Shoes does "free" in that you buy one pair and they give another pair away for free. Free sometimes means free for a while, or free up to a point where you have to start paying, or free without any great features. I've been testing the free version of  Buffer lately, but the "real" business version costs $100 per month.

The reason you should steal the Fortnite business model is because Epic is giving away something for free that normally costs a hefty amount. No strings attached, no subscriptions. Many Xbox One games cost north of $50 these days. Similar survival games like Playerunknown's Battlegrounds cost $30, but many console games cost $60.

The same business model could be used for a well-funded startup. Let's say you make a radical new product like a running shoe or new adapter for an iPhone. You make it totally free, but the customizations are where you make a profit, or the cosmetic updates, or an alternate version. Customers suddenly flock to your free product, and buy other products you sell. (Epic not only makes other paid games, but makes the engine for other paid games.) It's a brilliant model because it attracts a massive new customer base.

My theory about why Fortnite became so popular so quickly is based almost entirely on the lack of any price at all and the fact that the game is really fun. Here's a typical conversation I've heard several times now. Someone will bring up the game in casual conversation. Someone else will pull out their phone and look it up, and see that it says "get" in iTunes. If you go to the website for Fortnite, you'll see a download button. From there, you barely have to register. I timed how long it took me to download, register, and start playing Fortnite on a new laptop and it was all of about five minutes. On an iPhone it's even faster. To be able to play a full-scale survival shooter with 100 players (in the Battle Royale version) without paying a dime and without any pain is amazing.

Making a product that easy to download and play, without any costs, is brilliant for several reasons. The game itself is easy to play (although it takes a lot of effort to actually win), so the painless business model starts when you do a search and continues all the way through your first weeks or months of playing the game. You never have to enter a credit card. You don't have to visit a retail store. You just click, download, and play. I know of a few gamers who started playing after a web search...months later, they're still playing.

Most of us can't quite match that business model (for an accounting firm or a company that sells iPhone cases), but we can certainly mimic the basic concept of a painless experience. Apple does the same thing. When you buy a new MacBook, the unboxing and setup experience is just as enjoyable and intuitive as the shopping experience in the store. Microsoft finally started streamlining the Windows setup process as well in Windows 10, even adding a few snarky comments and the ability to use the Cortana bot to help.

Every product that knows how to streamline shopping, ordering, using, and learning a new product already has a leg-up on products that are hard to use and learn. Amazon is another great example--they know what customers want and streamline constantly.

Can you offer a free product that is normally expensive? Maybe not. The warning here is that a new shoe, or a new adapter, or a new set of earbuds that you give away for nothing could also lead to total bankruptcy. But there might be services or extras you can provide for free, and you can make the experience of buying your product "free" and easy. There are lessons to learn. If you start a company, you might be able to smash into a new market by offering a product for free that is normally only available for a fee. 

Fortnite has set the example for everyone to follow. Will you?