The closest alternative to gpt-oss-120b is Gemini 3.1 Flash Lite Preview — comparable intelligence (33.5 vs 33.3); for a cheaper option, Nemotron 3 Ultra (free) runs Free/M vs $0.039/M; and the best open-weight substitute is MiniMax M3.
Gemini 3.1 Flash Lite Preview is the closest alternative to gpt-oss-120b, with an Intelligence Index of 33.5 (gpt-oss-120b scores 33.3) at $0.250 per million input tokens.
Yes — Nemotron 3 Ultra (free) costs Free per million input tokens versus $0.039 for gpt-oss-120b, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to gpt-oss-120b — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.