The best free alternative to QLab is Linux Show Player, which is also Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to QLab and five of them is free so hopefully you can find a suitable replacement. Other interesting free alternatives to QLab are VPT (Free), Go Button (Freemium), HeavyM (Freemium) and MapMap (Free, Open Source).
Linux Show Player (LiSP) is a free cue player designed for sound-playback in stage production. The goal of the project is to provide a complete playback software for musical plays, theater shows and similar.
Linux Show Player vs QLab opinions
pros, cons and recent comments
Open source software under heavy development, awesome community.
Go Button is a mobile audio app designed to provide professional playback of music and sound effects for live shows. It provides a creative, self-contained show control system that runs on your iPad, iPhone, or iPod touch.