Independent travel is free, but you have to do your homework on itineraries.
Tips
usage
Contrasts with 跟团游 (guided group tour) and 半自由行 (semi-independent, flight+hotel bundle but free days). 穷游 (budget travel) is a related but distinct term.
culture
Hong Kong 自由行 also historically refers to the Individual Visit Scheme for mainland tourists, launched in 2003.