Free on the Microsoft store: https://www.microsoft.com/en-gb/p/play-playerunknowns-battlegrounds-full-product-release-free-for-a-limited-time/c4ff5wjxxq2m?irgwc=1&OCID=AID681541_aff_7794_1246483&tduid=%28ir__lvnddzuexhp26u2icjs9yibzx32xkektzg2t0pyo00%29%287794%29%281246483%29%28%282a0e6142953e92834192ce8235582d8c%29%28266696%29%281018132%29%281641950773%29%28%29%29%282a0e6142953e92834192ce8235582d8c%29&irclickid=_lvnddzuexhp26u2icjs9yibzx32xkektzg2t0pyo00&activetab=pivot%3Aoverviewtab

It's only for Xbox One, but you can add it to your library on PC.