Honestly, it's not that easy to find it for free legally. Maybe check out some lesser-known streaming websites, but there's a risk of poor quality or even potential legal issues. Your best bet could be waiting for it to be available on a mainstream platform with a free promotion.
Well, sometimes public libraries have digital collections where you could watch it for free. Also, some TV channels might air it around Christmas time without any charge. But you'd have to keep an eye on the schedule.
You might be able to find it for free on some streaming platforms that offer free trials or limited-time free viewing. But be careful as not all such sources might be legal or reliable.