Previews for Far Cry 5 are beginning to reveal a microtransaction system. It doesn't include loot boxes, but does include in-game currency that can be purchased for real-life money. The currency is called Silver Bars, and they can also be found within the game at outposts. It's hard to say at this point whether or not you'll only find them once at an outpost, or if it will automatically/manually reset.
A menu option will pop up when you find your first Silver Bar(s) in the game. It informs you that you can buy prestige weapons, vehicles, clothes, and skins from any shop in Hope County. The store option in the pause menu will offer some additional purchase options. It would make sense if gun skins, vehicle skins, and character outfits will also be buy-able with Silver Bars.
We don't know right now how much these Silver Bars will cost in real money. And we also don't know if all cosmetic items will be hidden behind them. It stands to reason that there will probably be other cosmetic items that you can acquire with more regular in-game currency. Those purchasable with Silver Bars might just be more rare/exclusive.
As we get closer and closer to Far Cry 5's March 27, 2018 release date, we're sure to learn more about these Silver Bars and their cost. For now, fans can rest assured that loot boxes have not been included in the game, but microtransactions have.
Source: PC Gamer