C-Stacks in Payday 3 are a special premium-style in‑game currency mainly used for higher-end gear and cosmetics rather than basic progression.

What C-Stacks Are Used For

  • Buying preset weapons that come with strong, pre-built setups and can be better than early-game custom builds.
  • Unlocking and buying weapon mods and sometimes extra weapon slots, letting you push your favorite guns further.
  • Purchasing cosmetics such as masks, suits, gloves, weapon charms, and paint patterns for masks and weapons.
  • Picking up certain high‑tier vendor items that are specifically priced in C-Stacks instead of normal cash.

In practical terms: you use cash to get C-Stacks, then use C-Stacks for nicer guns and drip.

How You Get And Spend Them

  • You buy C-Stacks from Setaggi, the currency vendor on the main menu between heists.
  • They’re sold in packs of 1, 5, or 10 , and each purchase of a given pack size makes the next of that size more expensive.
  • The exchange rates reset weekly , so there’s a soft cap on how many cheap C-Stacks you can grab per week.
  • Once you convert cash into C-Stacks, you cannot convert them back into cash, so you’re committing that money to cosmetics/weapon stuff.

Quick Example Use-Case

Imagine you’ve got your favorite rifle but it’s missing key attachments and you want a flashy mask:

  1. Run heists and stack up cash.
  2. Visit Setaggi and buy a batch of C-Stacks (start with the cheaper 1 or 5 bundles).
  1. Go to the vendors and spend those C-Stacks on a preset weapon or critical mods, then on a mask/suit you like.

Many players see C-Stacks as the “endgame polish” currency: you use them to round out your build and style once you’ve already got a decent pile of heist cash.

TL;DR:
C-Stacks are a special currency you buy with cash and then spend on powerful preset weapons, weapon mods/slots, and cosmetics (masks, suits, charms, paints), with prices that scale up and reset weekly.

Information gathered from public forums or data available on the internet and portrayed here.