Browsing is free
You can use the SubsMovies catalog and saved list without paying or registering here. The offer for a video is a separate choice. Open a title, set your viewing country and select Watch now to compare its JustWatch results.
Read the offer type
Free with advertising, included in a subscription and paid rental are not the same arrangement. Check the destination for the current price and access terms. A free trial is also different from an indefinitely free movie. Make the choice that fits the viewing you intend to do.
For television, check the season
A service may list a show while the season you need has different availability. Compare the actual season, language tracks and supported device. If nothing suits tonight, save the show and choose another title instead of assuming its catalog page promises a free stream.