You can buy a $10 subscription for a month to generate the training data, then cancel your subscription. The trained model is yours to use (and share with others) forever.
Which 5$ is a pretty easy sell if its useful in any way, It's pretty easy to justify a purchase if its yours forever and doesn't use much CPU so is easy to run I mean people were spending 1000$+ on mac mini setups to run local llms or run remote agents.
They also used Astra for the coding, which they can't get on a $10 subscription. And then there's the actual training cost.