How does looting work in Frosthaven?
Loot a token and you draw a loot card. Money and materials arrive at the end of the scenario; a random item goes into your pool immediately.
A loot token is removed from the map when looted. Monsters that loot get nothing extra; a character draws one card from the loot deck, unless the deck is empty.
The card's contents arrive at different times. Money and material resources are collected at the end of the scenario. A random item is different: you draw from the random item deck right away, add it to your pool and can use it for the rest of the scenario, even if that puts you over the item limit.
If the random item deck is empty, that card counts as a money card worth three coins. When a monster dies, a loot token is placed in its hex, which is where most of the deck gets used.
“If the loot card provides money or resources, the looting character does not gain them until the end of the scenario.”
Rules change with errata and with digital patches. If your copy of the book disagrees, the book wins — the official Frosthaven FAQ is the next place to look.