How much does it cost to run an AI agent?
API-Based Costs
If you use a commercial API like OpenAI's GPT-4, you pay per token. As of 2025, GPT-4 costs around $0.03 per 1,000 tokens for input and $0.06 for output, though prices change. A simple agent task might use 1,000–5,000 tokens, costing $0.03–$0.30. Complex tasks with many tool calls can exceed $1 per run.
For high-volume applications, costs add up quickly. For example, 10,000 tasks per month at $0.10 each would be $1,000. Cheaper models like GPT-3.5 Turbo cost about 10–20% of GPT-4, but may be less capable.
- Pay-per-token pricing varies by model and provider.
- Tool calls and retries increase token usage.
- Batch processing can reduce costs.
- Monitor usage to avoid surprises.
Self-Hosted and Infrastructure Costs
Running open-source models like Llama 3 on your own hardware eliminates per-token fees but requires GPU servers. A cloud GPU instance might cost $0.50–$2 per hour, or $360–$1,440 per month if run continuously. You also need engineering time for setup and maintenance.
Other costs include vector databases, monitoring tools, and storage. For a small-scale agent, total monthly costs could be $100–$500; enterprise deployments can reach thousands.
- GPU instances cost $0.50–$2 per hour.
- Engineering and maintenance time adds up.
- Storage and database fees may apply.
- Spot instances can reduce cloud costs.
Common mistakes
- Underestimating token usage from tool calls and retries.
- Forgetting that prices change frequently; always check current rates.
- Assuming self-hosting is always cheaper; it requires significant upfront investment.
