Unfortantly I have limited free weights,and my goal is muscle mass.I have some decent gains so far,but wish for much more.I only have about 120 pounds of free weights,and I can bench press that far to many reps,inclined,declined,sitting,standing,etc.I need some advice on how to get more out of the weights I have .is it as simple as doing many more sets and reps.I was told that if you wanted to get bigger you had to lift bigger,and this is my problem.I can't lift more weight because I simply don't have more and can't afford gym membership.

There is a lot more to lifting weights than bench pressing. Do squats, deadlifts, stiffleg deadlifts, bentover barbell rows, dips, pull-ups, lunges, walking lunges, plank, hyperextensions, barbell curls, overhead extension, pull-overs, weighted crunch, calf raise. If they are too easy for you, do one legged or one arm versions. Or try compound moves like clean and press, or overhead squat.

When you can do all those, ask around about buying more plates to add onto your kit.