I got to the same conclusion another way. There's ~2.6million seconds a month and this is getting 0.5tok/s which is 1.3million tokens a month. Give some room for overhead and a reasonable rule of thumb;
The cost to run the machine per month is the cost per million tokens.
Shit, beats the hell out of GitHub CoPilot charging $.01 per "credit." For Opus that's one credit for 400 tokens genned, so $5 converts to 200k tokens down, plus the cost of whatever context you sent up.
The cost to run the machine per month is the cost per million tokens.