They mention it explicitly in the Twitter post [0].

> Pricing: Input: $2.0 / M tokens Output: $6.0 / M tokens Implicit Caching: $0.25 / M tokens

[0]: https://x.com/Alibaba_Qwen/status/2084100707423289643

The linked qwencloud page has pricing; it's $2/6.

https://www.qwencloud.com/models/qwen3.8-max