There are a small number free Usenet servers available around the world. They tend to be slower and less reliable than paid services. Also, they typically do not provide SSL connections, and they have a short article/binary retention time (10 – 100 days).
I recommend trying a paid Usenet provider — they only cost about $10 per month.
Here’s my list of the best free Usenet servers:
Newshosting allows a 30 GB download limit on their trial accounts, and they give you access to the same service as a regular account. This includes access to their newsreader that has a built-in index search, and the ability to preview videos if there is a message with video attachments. They offers SSL connections and 2102 Days Retention.
Payment is via Paypal or credit card. Exact terms are “Free Trial is over in 14 days or 30GB used, whichever comes first. Free trial is offered for new customers only, one per customer.”
UsenetBucket is a straightforward company, known for fulfilling their promises (in terms of download limits and server speed). They are also known for accepting PayPal.
While testing their sign-up process, I did find that their email and IP check is a bit stringent, probably because they don’t require a credit card.