Along those lines, if you have never had a TR account before, you can request and use a 30 day trial here:
Also, Zwift will give all riders (even those who are not actively paying) 25km of free use every month. It’s been mentioned in other threads. People use that to sneak in a single race or group event once a month.
Additionally, RGT Cycling offers a free level with some limited options, but not distance restriction.