Anyone tested how many tokens the 20$ Codex subscription gets you compared to V4 flash on the deepseek API?

I'm finding myself spending 5-7$ daily on the deepseek api, so even with a crazy 99% cache hit, costs are starting to get out of hand. Given that Luna from OpenAI is reportedly close to DeepSeek Flash in capabilities, I'm wondering if I should get the 20$ subscription to offload some of the cost I'm currently spending on deepseek? OpenAI is not very transparent about limits, so it's unclear to me whether it's worth it or whether I'm just going to spend the entire week's limit in two hours.