LLM prices / Cheapest / Chatbot
AI API prices · 29 models fit · checked Oct 23, 2026
Cheapest LLM for a chatbot
Short answerClaude Haiku 5.5 and GPT-6 Luna tie for the cheapest current model for a chatbot reply at $0.35 per 1,000, standard price. At 30,000 a month that is $10.50. Next: GPT-5.6 Luna at $0.78 and DeepSeek Flash at $0.93 per 1,000. 29 of 29 current models fit this job. Ranked by cost only; we don't score quality.
Every model that fits, cheapest first
One chatbot reply = a 1,500-token prompt (system prompt plus the conversation so far) and a 400-token reply. Each model is billed the cheapest way its price list allows.
| # | Model | Per 1,000 | 30,000 a month | 300,000 a month | Billed | Context |
|---|---|---|---|---|---|---|
| 1 | Claude Haiku 5.5Anthropic | $0.35 | $10.50 | $105 | standard | 1M |
| 2 | GPT-6 LunaOpenAI | $0.35 | $10.50 | $105 | standard | 1.05M |
| 3 | GPT-5.6 LunaOpenAI | $0.78 | $23.40 | $234 | standard | 1.05M |
| 4 | DeepSeek FlashDeepSeek | $0.93 | $27.90 | $279 | standard | 1M |
| 5 | Gemini 3.1 Flash-LiteGoogle | $0.97 | $29.25 | $292 | standard | 1.05M |
| 6 | Gemini 3.5 Flash-LiteGoogle | $1.45 | $43.50 | $435 | standard | 1.05M |
| 7 | Gemini 3 Flash PreviewpreviewGoogle | $1.95 | $58.50 | $585 | standard | 1.05M |
| 8 | Gemini 3.8 FlashGoogle | $2.62 | $78.75 | $788 | standard | 1.05M |
| 9 | Gemini 3.6 FlashGoogle | $2.62 | $78.75 | $788 | standard | 1.05M |
| 10 | GPT-5.4 miniOpenAI | $2.93 | $87.75 | $878 | standard | 400K |
| 11 | DeepSeek V4 ProDeepSeek | $3.56 | $107 | $1,069 | standard | 1M |
| 12 | Claude Sonnet 5.5Anthropic | $7.00 | $210 | $2,100 | standard | 1M |
| 13 | GPT-6.1 SolOpenAI | $7.00 | $210 | $2,100 | standard | 1.05M |
| 14 | GPT-6 SolOpenAI | $7.00 | $210 | $2,100 | standard | 1.05M |
| 15 | Gemini 4 ArgonGoogle | $7.00 | $210 | $2,100 | standard | 1.05M |
| 16 | GPT-5.6 TerraOpenAI | $7.80 | $234 | $2,340 | standard | 1.05M |
| 17 | Gemini 3.1 Pro PreviewpreviewGoogle | $7.80 | $234 | $2,340 | standard | 1.05M |
| 18 | GPT-5.2OpenAI | $8.22 | $247 | $2,468 | standard | 400K |
| 19 | GPT-5.4OpenAI | $9.75 | $292 | $2,925 | standard | 1.05M |
| 20 | Claude Opus 5.5Anthropic | $14.00 | $420 | $4,200 | standard | 1M |
| 21 | GPT-5.6 SolOpenAI | $14.00 | $420 | $4,200 | standard | 1.05M |
| 22 | GPT-5.5OpenAI | $19.50 | $585 | $5,850 | standard | 1.05M |
| 23 | chat-latestOpenAI | $19.50 | $585 | $5,850 | standard | 400K |
| 24 | Claude Fable 5.1Anthropic | $35.00 | $1,050 | $10,500 | standard | 1M |
| 25 | GPT-6 AstraOpenAI | $35.00 | $1,050 | $10,500 | standard | 1.05M |
| 26 | GPT-5.6 CyberOpenAI | $48.75 | $1,462 | $14,625 | standard | 400K |
| 27 | GPT-5.2 ProOpenAI | $98.70 | $2,961 | $29,610 | standard | 400K |
| 28 | GPT-5.5 ProOpenAI | $117 | $3,510 | $35,100 | standard | 1.05M |
| 29 | GPT-5.4 ProOpenAI | $117 | $3,510 | $35,100 | standard | 1.05M |
What moves the answer
- Input price matters most here. The job reads 4x more than it writes, so the input (and cache-read) price drives the bill.
- Watch long prompts. 13 of these models charge more once a prompt passes a size threshold (for example Claude Haiku 5.5 above 100,000 tokens); this job stays under it, a bigger one may not.
Method
Prices: each provider's own pricing page, checked Oct 23, 2026. Fits: current on the provider's model page (not deprecated, legacy or shut down), and a context window that holds the request; checked Oct 24, 2026. Cache writes are not counted. This page ranks price only; quality on your task is a separate test. People search for this: Google suggests "cheapest llm for chatbot".