Official ruleBase game, 6th edition (2025) and 5th edition
Can you give resources away for free in Catan?
NoShort answer
No. You can't give away cards in any way. A trade has to go both ways, and you can't trade a resource for the same resource.
The rule
Trades must involve cards moving both ways. Giving cards away for nothing isn’t allowed.
You also can’t trade identical resources, such as 3 ore for 1 ore. That counts as giving cards away.
The ratio is up to the players: 1 card for 3 is fine if both sides agree. Development cards can’t be traded or given away at all.
Example
Ben is about to win, so Kai offers to hand Ana 2 brick for free so she can build first. That's not allowed. Kai has to get at least 1 card back.
Why players argue about it
Gifts look harmless, and some groups allow them to help a player who's stuck. They also let players team up against the leader. Both editions rule them out.