Back in the 2015 Christmas Event, you could get this godly knife by buying 75 Gifts through the shop. That event is long over, so now the only way in is through trading. For traders, Xmas sits well below neighbors like Eternal, Hallow's Edge and Handsaw. It's a slow, collector-flavored item rather than a hot trade.
Xmas is a Godly knife in Murder Mystery 2. Its combined value is 8.5, #106 of 146 godly items and #361 of 921 valued items overall. Demand is very low: it sits in inventories for a while, and buyers often ask for a discount.
Closest in value: Eternal (8.5), Hallow's Edge (8.5), Handsaw (8.5). Use them as a benchmark for a fair one-for-one trade.
Value history
What it is worth in other items
1×Eternal
1×Hallow's Edge
1×Handsaw
1×Tailslide
1 : 1.1Bioblade
1 : 1.1Eternal III
1 : 1.1Eternal IV
1 : 1.1GhostHow many of each item equal one Xmas by value. Demand differs between items, so check it before you trade.