I just ran some numbers and it works out if you're a prolific user.

Over 9 days I would have spent roughly $63 dollars on Codex with 11.5M input tokens plus 141M cached input tokens and 1.3M output tokens.

That roughly mirrors the $100-200/wk in API spending that drove me to the subscription.

  | Category | Tokens | Rate (/1M) | Estimated Cost |
  |---|---:|---:|---:|
  | Input (uncached) | 11,568,331 | $1.75 | $20.24 |
  | Cached input | 141,566,720 | $0.175 | $24.77 |
  | Output | 1,301,078 | $14.00 | $18.22 |
  | Total | 154,436,129 | — | $63.23 |

It makes sense though for heavy use.