Cheapest AI APIs in 2026: Every Model Ranked by Cost

Looking for the cheapest AI API? I got tired of checking 7 different pricing pages every time I needed to pick a model, so I built AI Pricing Guru — a free comparison tool that tracks token costs across all major providers, updated daily.

Here's the current ranking as of March 2026.

Cheapest AI Models: Input Price Ranking

Rank	Model	Provider	Input / 1M	Output / 1M
1	GPT-4.1 nano	OpenAI	$0.10	$0.40
2	Mistral Small	Mistral	$0.10	$0.30
3	Llama 4 Scout	Meta	$0.15	$0.15
4	GPT-4o mini	OpenAI	$0.15	$0.60
5	Llama 4 Maverick	Meta	$0.20	$0.20
6	GPT-5.4 nano	OpenAI	$0.20	$1.25
7	Grok 4.1 Fast	xAI	$0.20	$0.50
8	GPT-5.4 mini	OpenAI	$0.25	$2.00
9	Gemini 2.5 Flash-Lite	Google	$0.25	$1.50
10	DeepSeek V3.2	DeepSeek	$0.28	$0.42

Best Value by Use Case

Use Case	Best Model	Monthly Cost (10M tokens)
Classification/routing	GPT-4.1 nano	$5
Chatbots	Mistral Small	$4
Code generation	Grok 4.1 Fast	$7
Document analysis	Llama 4 Scout	$3
Complex reasoning	DeepSeek V3.2	$7
Multimodal	Gemini 2.5 Flash	$28

The Hidden Savings: Cached Input Pricing

Most providers offer 80-90% discounts on repeated prompts (system prompts, shared context). If your app reuses the same context:

• OpenAI: 90% off (e.g., $2.50 → $0.25)
• Anthropic: 90% off
• DeepSeek: 90% off ($0.28 → $0.028)

Design stable system prompts and you'll cut costs dramatically.

How to Save Even More

1. Batch API — OpenAI offers 50% off for async processing
2. Right-size your model — don't use GPT-5.4 for tasks GPT-4.1 nano handles
3. Monitor usage — use a token calculator to estimate before committing
4. Cache aggressively — same system prompt = cached pricing

Full Comparison

I track 33 models across 7 providers with daily updates. Check the full comparison:

• 🔗 Full pricing table
• 🧮 Token cost calculator

All data is free, no signup required. I update prices daily by checking each provider's official docs.

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Built this because I was wasting time comparing pricing pages manually. Hope it helps someone else too.