Obtained by reaching the 20th tier of the Christmas Event 2020 main rewards for Snow Tokens, so it's been trade-only since the event ended. Collectors of old event knives still look for it, though the ancient rarity and winter look matter more to set builders than to fast traders.
Icebreaker is an Ancient knife in Murder Mystery 2. Its combined value is 67.5, #9 of 20 ancient items and #169 of 921 valued items overall. Demand is low: it sits in inventories for a while, and buyers often ask for a discount.
Closest in value: Darkknife (67.5), Green Pumpkin (2018) (65), Heartblade (65). Use them as a benchmark for a fair one-for-one trade.
Value history
What it is worth in other items
1×Darkknife
1×Green Pumpkin (2018)
1×Heartblade
1 : 1.1Black Cat
1.1×Chroma Darkbringer
1.1×Glitch1
1.1×Ornament
1 : 1.1PearlHow many of each item equal one Icebreaker by value. Demand differs between items, so check it before you trade.