Are you familiar with actually good & free TRPG demos which help you to jump into play without proper experience and and get the gist of the game in one-two hours?
I am not looking for general starter sets, or little pre-packed games, but more like pre-packed introductory adventure modules with pregen characters and all the necessary rules both for players (and GMs, if there is any) to convey the essence of the gameplay & setting.