In the past, I would have said faucets, but there are fewer and fewer reliable ones (the most famous, freebitco.in, is having issues), and they're mostly going to be a waste of time.

The only more plausible option would be to participate in signature campaigns on the forum in the future. It's free in the sense that you won't spend money to acquire satoshis, but you'll need effort and time to achieve it. To do this, you need to participate in the forum regularly, making constructive contributions and, importantly, not breaking the rules. Do not plagiarise, and do not use AI without citing it. If you do this, in about six months, you could be participating in signature campaigns and earning around 40 or 50 dollars per week in Bitcoin.