https://openrouter.ai/openrouter/free - 200K Context Length | https://openrouter.ai/compare/openrouter/free/openrouter/auto

https://opencode.ai/docs/zen/#pricing

Model   Input   Output  Cached Read Cached Write
Big Pickle  Free    Free    Free    -
MiMo V2 Pro Free    Free    Free    Free    -
MiMo V2 Omni Free   Free    Free    Free    -
Nemotron 3 Super Free   Free    Free    Free    -
MiniMax M2.5 Free   Free    Free    Free    -
GPT 5 Nano  Free    Free    Free    -