GPT3 is 800GB, which is about as large as the largest torrent files out there. GPT4 size is unknown, so I can't comment. While I haven't run the actual numbers (life is short), assuming a GPT3 torrent, my sense is that the cost of running it would be under $1M, possibly under $100k. Compared to (hundreds of?) $B for a state-level nuclear weapons program.

But yes, technically I was wrong. It is not 'practically free', it is 'within the budget of e.g. a race boat enthusiast'.