Mistral Small 4 is the cheapest at $0.15/$0.60 per million tokens — 96% cheaper on input and 97% cheaper on output. For a model with similar coding capabilities, DeepSeek V4 Pro at $0.435/$0.87 offers the best balance of quality and cost savings (83% cheaper).

DeepSeek V4 Pro costs $0.435 input / $0.87 output per million tokens, compared to Codex's $2.50/$10. That's 83% cheaper on input and 91% cheaper on output. For a typical workload of 1M input + 500K output tokens per month, you'd save approximately $19,172 per year.

Claude Sonnet 4.6 at $3.00/$15 per million tokens is slightly more expensive on both input (20% more) and output (50% more). However, it offers 200K context and excellent coding performance. The premium is justified if you need Anthropic's superior code quality for complex refactoring.

Mostly yes. Most alternative providers offer OpenAI-compatible APIs, so switching often requires just changing the API endpoint and key. DeepSeek, Together (Llama), and several others support the OpenAI API format directly.

For code generation, DeepSeek V4 Pro ($0.435/$0.87) offers strong coding performance at 83% less cost. GPT-5 ($1.25/$10) is also excellent for code and 50% cheaper on input. Claude Sonnet 4.6 ($3/$15) is the quality leader but costs more. Choose based on your quality/cost requirements.