TurboScribe Free Tier (3 files per day, up to 30 minutes each)
TurboScribe
Free tier (100% Free): transcribe 3 files for free every day, each file up to 30 minutes long, uploading 1 file at a time, with lower processing priority; email sign-up is enough
Verbatim from the Free tier on the official pricing page: "100% Free / 3 Transcripts Daily: Transcribe 3 files for free every day. / 30 Minute Uploads: Each file can be up to 30 minutes long. Upload 1 file at a time. / Lower Priority" The sign-up entry is labeled "Sign up with email address".
By the official figures that is at most about 90 minutes of audio transcribed per day; the free tier has lower priority and may queue at peak times. The paid tier's upload length and file count were not read from the official page this time. Whether Chinese is supported and the recognition quality are unverified. Reachability from mainland China was not tested.