Low Cost AI Workflows: Model Selection Guide — Cromus
Most teams default to frontier models for every workflow step, resulting in 3-10x overspend on tasks that don't need premium capability. Low cost AI workflows require matching each step to the right model tier — Eco, Cost, Balanced, Quality, or Open Source — based on task complexity, not model popularity.
Cromus organizes 60+ verified models across 11 providers (OpenAI, Anthropic, Google, xAI, DeepSeek, Mistral, Meta, Cohere, Amazon, Microsoft, Qwen) into five tiers with verified pricing. The Eco tier (Mistral Small 4 at $0.15/1M tokens input) handles classification and extraction. The Cost tier (DeepSeek V4 Flash at $0.14/1M tokens input) covers general tasks. The Balanced tier (Claude Sonnet 4.6 at $3.00/1M tokens) handles coding and agents. The Quality tier (GPT-5.5 at $5.00/1M tokens, Claude Opus 4.7 at $5.00/1M tokens) covers complex reasoning. Open Source (Llama 4 Maverick, Gemma 4 27B) eliminates per-token costs entirely.
Croms (units of preventable AI workflow waste) identify cost waste through a weighted formula: 35% cost waste, 25% latency overhead, 25% failure risk, 15% structural gaps. A high Croms score on a cheap model still indicates waste — redundant steps, missing caching, and serial execution multiply per-run costs across thousands of executions.
Real-world model downgrades show significant savings: keyword clustering moved from Quality to Cost tier saves 94%, GEO audits moved from Quality to Balanced tier saves 40%, while schema QA stays on Quality tier because downgrading increases failure rate and rework cost.