원문에는 1k 토큰당 $0.002로 나와있네요.

It is priced at $0.002 per 1k tokens

그리고 토큰의 정의가 궁금해서 조금 더 찾아보니 in/output 글자 수에 따라 정해지나봐요.

The number of tokens processed in a given API request depends on the length of both your inputs and outputs. As a rough rule of thumb, 1 token is approximately 4 characters or 0.75 words for English text.