The latest PayDay 2 update adds random drops containing various items including 'Safes'; these can't be opened up unless you purchase a 'Drill' for €2.20/$2.50 in real money.
It's the first real appearance of microtransactions in the game, which has of course had a bucketload of additional DLC. Safes contain new weapon skins, but also - and here's the problem - have a chance of boosting each gun's stats.
That might not be so much of an issue in a F2P game, but Payday 2 is full price retail - yet unless you splash out more cash, you're going to be at a distinct disadvantage. The game's already stacked in favour of those players who've bought weapon DLC, and this latest move hasn't been welcomed with much warmth from the community
The Black Market update is part of the 10-day Crimefest event, which celebrates the anniversary of the original game.