Following the second State of Play presentation on May 9, 2019, Capcom has begun a free Monster Hunter World trial for PlayStation 4 owners. Until May 20, 2019, people can begin sampling and enjoying the adventure on their consoles. It is a 14.3 GB download via the PlayStation Store.
The free Monster Hunter World trial allows people to take on eight different assignments. Essentially, you have access to the beginning of the game. You can get up to Hunter Rank 4 and access some three-star quests set in Ancient Forest and Wildspire Waste. (The last mission you can take is Flying Sparks: Tobi-Kadachi.) The Great Jagras, Kulu-Ya-Ku, Pukei-Pukei, Barroth, Jyuratodus, and Tobi-Kadachi can be fought, though you may also encounter a Rathalos in the Ancient Forest or Diablos in Wildspire Waste.
People with the trial version can play with those who have the full version. Someone could also carry over save data from this trial and continue playing in the full version of Monster Hunter World. However, once you do carry over the save, you can no longer use it with the trial. People who already own the full version can not roll back to the trial version.