Feature Request: Integrate Token Usage Cost Calculation Based on OpenAI's Pricing

Hello,

Token Usage Cost Calculation:
I would like to request the addition of a feature that calculates the cost of token usage based on OpenAI's current pricing. This feature would allow developers to estimate the cost directly while using Tiktoken for tokenization.

Real-Time Pricing API:
While I understand that real-time pricing information was discussed in a separate issue (https://github.com/openai/openai-python/issues/2074), I believe it would be valuable to integrate this information into Tiktoken as soon as OpenAI provides an official API for retrieving current pricing.

Benefits:

• Cost Management: Helps developers manage their budget by providing instant token usage cost estimation.
• Optimization: Guides developers in optimizing token usage to avoid unnecessary costs.
• Convenience: Provides a seamless experience by consolidating tokenization and cost calculation in one place.

Thank you for considering this suggestion, and I look forward to any potential discussions!

The issue does not name a file, test, or entry point. Start by reviewing tiktoken's public API and the discussion in openai/openai-python issue 2074, then determine whether an official OpenAI pricing API exists. Done would require an agreed pricing source and a defined interface for calculating token costs.