One way is to have preordered the $40 deluxe edition of the game. Anyone who did so obtained the PLAYERUNKNOWN costume set, which included the trench coat among many other things. As of now, you can purchase the costume set on the Steam Community Market, but it will cost upwards of $466.
The other way to get it is to simply purchase the trench coat on its own. As of right now, it costs $185, and the price will continue to steadily climb because of the high demand.
There’s no free way to obtain this item, and you could purchase 3 games with the money you spend to get your hands on it. Why is it so sought after?
Because there’s a practical reason for it. This black coat is good camouflage in dark environments, making it hard for somebody to spot you. That means it’s easier for you to ambush people, evade trouble, or simply sit and wait for everybody else to kill each other.
Of course, there’s also the fact that it simply looks cool. Ever since The Matrix, or maybe even before, trench coats have always carried the connotation of ‘badass’. As Counter Strike: Global Offensive has shown, people are willing to pay ludicrous amounts of money to have a cool looking skin that has no effect on gameplay. Perhaps that’s all there is to it.
Either way, you’re going to have to seriously shell out if you want this trench coat – and all its advantages – for yourself. It doesn’t look like it’s going to get cheaper any time soon.