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Cheapest LLM APIs for side projects (2026)

Lowest listed prices we found on official pages (USD per 1M tokens, checked 16 Oct 2026). Cheaper models are less capable; test on your task.

In this guide: FAQ

1. 1
   OpenAI API

   General-purpose models for your app

   Cheapest listed: gpt-5-nano at $0.05 input / $0.40 output per 1M tokens.

   Our notes · Website ↗ · Pricing checked 3 Nov 2026

   Paid fromFrom $0.05 per 1M input tokens (gpt-5-nano); gpt-6.1-sol $2/$10 per 1M in/outFree tier: Unknown
2. 2
   Anthropic API

   Coding and agentic workloads

   Cheapest listed: Claude Haiku 5.5 at $0.10 input / $0.50 output per 1M (prompts up to 100k tokens). Small free credits for new users.

   Our notes · Website ↗ · Pricing checked 10 Nov 2026

   Paid fromFrom $0.10 per 1M input tokens (Haiku 5.5); Sonnet 5 $2/$10 per 1M in/outFree tier: Small free credits for new users
3. 3
   Google Gemini API

   Long-context and multimodal apps

   Free tier on some models. We didn't verify the cheapest paid Gemini model.

   Our notes · Website ↗ · Pricing checked 9 Nov 2026

   Paid fromExample paid model: $2/$10 per 1M in/out, rising to $4/$20 from 1 Dec 2026Free tier: Yes for some models (not all)
4. 4
   OpenRouter

   One API key for many models

   One key for many models; per-model prices not compared here.

   Our notes · Website ↗ · Pricing checked 4 Nov 2026

   Paid fromPay-as-you-go at provider list prices; 5.5% fee on credit purchases (Standard)Free tier: Yes (25+ free models, 50 requests/day)

FAQ

Prices in USD from official pages. Anything marked unverified could not be confirmed.