In the sense that OpenAI had ~$2.5 billion of revenue 2024 but likely spent ~$3.8 billion just on inference.
Meaning they lose 50 cents for every dollar they spend to send you a token, more if you are a free user. This discounts employees, CapEx, real and imagined (1.4T), overhead, and training (subsidized by M$oft).
Thus, if you have a way to turn every token they give you back into USD, even at a discounted rate, you can and should rob them blind before the well dries up.
That doesn't mean the cost is negative, it means the profit is negative for openai.
I mean, sure, sign me up, and I'll use a bunch of negative-cost tokens...
???
Sure, there's zero cost tokens in the form free chatgpt, but negative cost implies that you're getting paid to consume tokens, which I'm not aware of?