I've been thinking about getting gym membership lately, just because using the machines at the gym would improve my form over using free weights but the advice I was given by the body builders in prison;

Gym membership is great if you are homeless, you get access to a shower and a place to rest indoors(you can't sleep overnight but most gyms do not care about people taking naps during the day)

The rowing machine is the best value for money but you don't need a gym to get big, with pullup bars, dip bars and a park bench you can train every muscle group (add weight to your body and increase reps for progressive overload.

And you won't make gains if you're not eating right and getting enough sleep.