How to reduce the cost of API usage?

How to reduce the cost of API usage without decreasing the quality of the model? I was thinking maybe by orchestrating multiple agents and specification of them we can be able to reduce the cost of API usage. because API is very expensive to use and chatgpt account is very limited

I’m handling my own costs by reducing the context window and instead summarizing whatever is outside the context window concisely in the system message under a “memories” section.

Prompt optimization is also important. Can the model do the same work with a more concise prompt that uses fewer tokens?

Also, think about the model you’re using. Do you really need the most expensive model for your type of work? For instance, gpt-5.4-mini or gpt-5.1 instead of gpt-5.4.

Whenever caching is used, you save money, but that’s mostly controlled server-side.

Just my two cents.